NORDIC LIGHT AND COLOUR Editors: Barbara Szybinska Matusiak Karin Fridell Anter

Transcription

1 NORDIC LIGHT AND COLOUR 2012 Editors: Barbara Szybinska Matusiak Karin Fridell Anter

2 NTNU - The Faculty of Architecture and Fine Art Edited by: Barbara Szybinska Matusiak and Karin Fridell Anter Graphic design: Ole Tolstad Printed by: NTNU-trykk 2013 ISBN NTNU - The Faculty of Architecture and Fine Art Alfred Getz vei 3 N-7491 Trondheim fak-adm@ab.ntnu.no

3 NORDIC LIGHT & COLOUR NORDIC LIGHT AND COLOUR In April 2012, NTNU held a PhD course titled Nordic Light and Colours. It was funded by NordForsk and originated from the inter-nordic transdisciplinary research project SYN-TES: Human colour and light synthesis. Towards a coherent field of knowledge. The course included the task to write an essay on a topic within the participant s own field of research, including both colour and light. This publication presents a selection of these essays, together with articles where lecturers present topics that were presented at the course or in other ways are relevant for its theme. All contributions have undergone a double blind peer review process, where internationally renowned colour and light experts have functioned as referees. The selection of articles includes a broad range of topics referring to questions and theories of different disciplines. Thus we hope that the publication will contribute to the formation of Colour and light as a coherent and multidisciplinary field of knowledge. Thank you to Monica Billger, Alex Booker, Jan Ejhed, Cecilia Häggström, Ulf Klarén, Thorbjörn Laike, John Mardaljevic, Karin Søndergaard, Arne Valberg and Helle Wijk who have functioned as lecturers, workshop leaders and/or referees. Without your contributions neither the course nor this publication would have become reality. Special thanks go to Kine Angelo who, besides being one of the course participants, helped with preparation of the course and with diverse practical issues during the course. Trondheim May 2013 Leaders of the PhD course in April 2012 and editors of this publication; Barbara Szybinska Matusiak Professor, architect MSA, PhD Leader of the Dep. Arch. Design, Form and Colour Leader of Light & Colour Group at NTNU Karin Fridell Anter architect SAR/MSA, PhD, Assoc. Prof. Leader of research project SYN-TES 1

4 CONTENTS Course Nordic Light and Colour held at NTNU in April Karin Fridell Anter & Barbara Szybinska Matusiak Spatial interaction between light and colour. 13 An overview over current international research. Karin Fridell Anter Nordic daylight 25 Barbara Szybinska Matusiak Levels of experiencing colour and light 39 Ulf Klarén, Harald Arnkil & Karin Fridell Anter Light as experiential material 47 Karin Søndergaard & Kjell Yngve Petersen Evidence-based health care design - how can it be measured? 67 Aspects of colour and light Helle Wijk Daylighting science: 73 A brief survey and suggestions for inclusion in the architectural curriculum John Mardaljevic Virtual environments to study daylight and colour. 95 Towards a new approach of advanced research method. Claudia Moscoso Light level perception in interiors with equiluminant colours 105 Veronika Zaikina Illuminating the Home according to the Danish Energy Savings Trust 123 From focusing on everyday life to focusing on technical terms. Charlotte Louise Jensen Professional s thoughts on light and colour in nursing home facilities 137 Susanna Nordin About the authors 146 Light & Colour Group at NTNU 147 2

5 NORDIC LIGHT & COLOUR COURSE NORDIC LIGHT AND COLOUR HELD AT NTNU IN APRIL 2012 Karin Fridell Anter & Barbara Szybinska Matusiak ABSTRACT This paper presents and discusses an intense six day PhD course held in One of its aims was to contribute to the formation of colour and light as a coherent field of knowledge. Both lecturers and participants represented a variety of professional and disciplinary approaches. To create a common platform for fruitful knowledge interchange there was a pre-course reading task and test. The course included lectures, workshops, and an essay task. It gave a broad interdisciplinary understanding of colur and light and their spatial interaction, as well as a network for possible future collaboration. 3

6 4 Workshop examining how the shape and borders of light patches affect our behaviour and emotions.

7 NORDIC LIGHT & COLOUR INTRODUCTION Our visual experience of space is formed in an interaction between light, colour and human perceptual ability. Even in a worldwide perspective there are, however, very few research projects or educational initiatives that investigate this interaction as a coherent field of knowledge (Fridell Anter 2013). In April 2012, a unique PhD course on light and colour was held at Norwegian University of Science and Technology (NTNU) in Trondheim, with funding from NordForsk and participants from four Nordic countries. The PhD course was initiated from the large Nordic research project SYN-TES.: Human colour and light synthesis: Towards a coherent field of knowledge ( which was carried out during by an interdisciplinary group of researchers and practical light and colour experts from Nordic universities and companies. One of the aims of the project was to enhance collaboration and understanding between different professions and disciplines working with colour and light; education at the PhD-level is a very suitable arena for this. GENERAL PRESENTATION OF THE COURSE The course was conducted in English. It was led by Professor Barbara Matusiak, leader of the Light & Colour Group at NTNU, together with Associate professor Karin Fridell Anter from University College of Arts, Crafts and Design (Konstfack) in Stockholm. The approach was genuinely interdisciplinary, with as much emphasis on light as on colour and involving a diversity of approaches such as physics, architecture, perception psychology, performance art, lighting design and health and care sciences. Apart from lectures, the course included workshops where participants could investigate different aspects of colour and light in the Room laboratory and Daylight laboratory of NTNU and at interesting indoor and outdoor places in Trondheim. The final step of the course was the writing of scientific essays that included both light and colour issues. In total the course gave 7,5 ECTS. Not only the lecturers but also the course participants represented a very broad competence. The course was open to PhD candidates at Nordic universities, with the demand that their thesis work should deal with light and/or colour. The seventeen participants were active in Norway, Sweden, Denmark and Finland and belonged to professions and disciplines such as civil engineering, art, architecture, nursing, design, environmental psychology, and architecture. This opened for many possibilities to learn from each other and to develop valuable professional connections for the future. At the end of the course, all participants gave a written anonymous course evaluation, which was very positive but also pointed out things that should be improved. The Light & Colour Group at NTNU hopes to be able to give the course again in spring 2014, in a slightly revised form. TO CREATE A COMMON PLATFORM One of the aims of the course was to create the preconditions for interaction between people with different professional and academic perspectives, and the course was open for PhD candidates within any subject, as long as their thesis work dealt with colour and/or light. Thus the field and level of knowledge differed much between the participants. Some of them had almost finished their thesis work, whereas others had started it very recently. Some had a professional background where colour and/or light were essential, such as architecture, art and design. Others studied colour and/or light issues within disciplines that have other central fields of interest, like environmental psychology and health science. This created an initial challenge to establish a common platform of knowledge, from which lectures, workshops and group discussions could start. We identified three important aspects of this knowledge platform. - a theoretical understanding of the fact that colour and light can be approached and studied from many different perspectives, and a recognition of the differences between them - an understanding of the Natural Colour System (NCS), which was to be used as the language for descriptions and analyses of colour during the course - an understanding of basic photometric concepts and terminology, which were necessary for understanding lectures and assignments during the course To achieve this, all participants were asked to read a number of texts and had to pass a pre-course test before being admitted. The main text dealt with the three knowledge traditions of perception, physics and psychopysics, and the colour and light concepts belonging to these traditions (Fridell Anter 2012). The same words for example the basic ones of colour and light are used within all these traditions, but they do not refer to the same thing. For example, the same amount of (photometric) light can mean different levels of (perceived) light, depending on the spatial context and the person s adaptation. Also, the same (physical) colour will be perceived differently depending on such as surrounding colours. These conceptual ambiguities had to be made clear, in order to make it possible to follow lectures and workshops and to facilitate communication between course participants from different knowledge traditions. 5

8 Workshop results showing the strong colouring effect of light reflected from coloured surfaces. 6 The traditional colour scale of Trondheim was examined in an outdoor workshop.

9 NORDIC LIGHT & COLOUR NCS terminology: Two of the following terms could (but need not) refer to colours having the same HUE. Which two? BROWN BLUE GREEN YELLOW BLACK NCS terminology: Two of the following terms could (but need not) refer to colours having the same NUANCE. Which two? PINK DEEP RED DARK BLUE LIGHT GREY WHITE Lighting: The table includes four important concepts dealing with lighting. For each one of them, write the corresponding unit (such as lumen, candela etc.) and place an X in the box telling if the concept says something about the light source, about the light falling on to a surface or about the light reflected from a surface..tells something about CONCEPT UNIT Light source Light falling on surface Illuminance Light reflected from surface Luminance Luminous flux Luminous intensity Examples of questions from the pre-course test. NCS, the natural colour system, is a model for describing all possible perceptions of surface colours through their degree of similarity to up to four out of six elementary colours (yellow, red, green, blue, white, black). (Hård et al. 1996; Svensk Standard 1997). It was chosen as the colour language of the course, and to be able to follow the course the participants were expected to understand its basic theory and concepts. For this purpose they were given a short introductory text and references to further reading. Photometric concepts and measurements like illuminance (lux) and luminance (cd/m 2 ) have to be understood in order to follow lectures and discussions that discuss light and lighting. The participants were given a short introductory text that presented the concepts and their interrelations, and gave some examples of their use. The pre-course test consisted of questions in a form that was primarily meant to disclose potential misunderstandings. See figure above for examples of such questions. Those who did not pass the test got comments from the examiner and a second chance, and finally all passed. Once the course started, it became clear that the pre-course literature and test had not been enough to convey the basic understanding intended. The photometrical concepts gave the least difficulties, which was obviously due to the fact that practically all participants had already worked with light issues. NCS, on the other hand, was new to several participants and others had only used NCS samples and codes instrumentally without considering the system behind them. During the course it appeared that the introduction of NCS was not enough to give the understanding that would make it useful in workshops and discussions, and some extra time was allotted to explaining it. 7

10 8 Full scale studies to create spatial atmosphere with light and colour

11 NORDIC LIGHT & COLOUR We can conclude that to make the course optimally valuable for students with so different backgrounds, more time must be used for creating a common conceptual platform. This could be done before the course or as its first part, possibly with two special sessions: light for colour people and colour for light people. When planning the next version of the course, this will be considered. LECTURES AND WORKSHOPS The schedule of the six course days was very intense and included all meals, jointly for lecturers and participants. All participants and several of the lecturers stayed in Trondheim during the course. The typical day included two lectures in the morning and two workshops in the afternoon. For the workshops, which were lead by the lecturers, the group was divided into two. One afternoon was used for a larger assignment without teachers. The lectures covered the following themes: Perception of light and colour. Professor Arne Valberg (Biophysics, NTNU) presented what is known and what is still not known about the complex relationship between physical stimuli and visual perception. Associate professor Ulf Klarén (SYN-TES group, Konstfack, Stockholm) demonstrated and discussed different levels of human perception and experience. Their joint conclusion was, that an understanding of human perception cannot be based solely on physical data. (Valberg 2005; Klarén 2012) Light and colour in Nordic countries. Professor Barbara Matusiak (Light & Colour Group, NTNU) presented criteria for daylight evaluation and classification in general (Matusiak 1998, 2005), and showed the specific visual character of northern daylight, such as low mean elevation angel of the Sun, low mean colour temperature of sunlight, high occurrence of cloud cover and the impact of snow and ice. Associate professor Karin Fridell Anter (SYN-TES group, Konstfack) presented the typical colour scales of vegetation and ground in mid-sweden and the exterior colour tradition of Swedish buildings, and discussed this in relationship to other Nordic countries (Fridell Anter 1996; Fridell Anter & Svedmyr 1996; Fridell Anter & Enberg 1997). Professor Alex Booker (Light & Colour Group, NTNU) showed his art exhibition Trondheim Derivé with photos and prints exploring the visual character of Trondheim and expressing the autonomy of colour. All this gave starting points for reflective viewing and consideration of the light and colours that form the outdoor environment that surrounds us and has formed our set of references. Spatial interaction of light and colour. Professor Monica Billger (Architecture, Chalmers, Gothenburg) showed, among other things, how colours in a room influence each other through induction and interreflection (Billger 1999). PhD Cecilia Häggström (Lighting Design, Jönköping University) demonstrated how our perception of form and space affects and is affected by our perception of colour and light (Häggström 2009). Associate professor Karin Søndergaard (Lighting lab, Royal Danish Academy of Fine Arts) showed how light can create spatial zones that relate to our body, feelings and behaviour. All this supported an understanding that the perceptual and experienced aspects of colour and light could not be analysed in a meaningful way without considering the spatial context. Light, health and well-being. The non-visual aspects of light are essential for our health and diurnal rhythm. In the course program this topic was presented by associate professor Thorbjörn Laike (Environmental psychology, Lund University) (Govén et al. 2010). Associate professor Helle Wijk (Health and care sciences, Gothenburg University) presented research and applications showing how colour and light can function as a support for visually and/or cognitively impaired persons (Wijk 1998). This gave a further understanding that light and colour should be seen as fundamental aspects of architecture and interior design. Daylighting and electric lighting. Professor Jan Ejhed (KTH Lighting lab, Stockholm) presented different possibilities to use artificial light and professor John Mardaljevic (Building Daylight Modelling, Loughborough University) demonstrated methods for adequate prediction of daylight measures in buildings. This emphasised the importance of adequate technical knowledge in the process of lighting planning, and showed both advantages and limitations inherent in the digital methods aimed to favour this process. Most of the workshops were based on the themes of the lectures and were held in the two well-equipped laboratories of the NTNU Light & Colour Group. The daylight laboratory is meant for model studies and has an artificial sky that provides diffuse light as from the sky, and two artificial suns that provide parallel light radiation and can be set in the accurate angel for any geographical place, date and hour. The room laboratory has large windows in two directions, but can also be made dark. It is equipped with elements for easy building of full scale spaces and a large number of different light sources. See edu/bff/laboratories. Two workshops were held in the historic parts of Trondheim. The nominal and perceived colours of facades were assessed, using the method s of Fridell Anter (2000), and the light situation in the famous Nidaros cathedral was evaluated, using the PERCIFAL method developed within the SYN-TES project (Klarén 2013). The participants course evaluation showed that all parts of the course were highly appreciated, but that there was generally too little time for each theme. Especially the workshops should have been given more time, which would have enabled a deep- 9

12 10 Investigations of the relativity of perceived form light colour.

13 NORDIC LIGHT & COLOUR er interaction between participants with different knowledge background. Another way of saying this is that there should have been fewer specified assignments and more freedom for participants to use the unique laboratories according to their own creative ideas. FINAL ESSAYS The last part of the course was to write an essay, discussing a topic relevant for the person s own thesis work from the joint perspective of colour and light. This task was optional and not all participants wrote essays. The essays came to cover a wide variety of research questions such as a full scale study on the use of virtual environments to study daylight and colour, a survey on how the colour rendering properties of light sources have been presented to customers and an interview investigation on professionals thoughts about light and colour in nursing home facilities. Some of the essays were offered publication in this peer reviewed publication together with articles by some of the lecturers. The essay work was meant to take 3 weeks full time work, corresponding to 4,5 ECTS. After some participants have finished their essays and others have choosen not to write, we can conclude that the allotted time was too short to lead to essays of the expected depth and quality. Those who successfully finished their essay work have, probably, spent much more time on this than three weeks. This means that in a future course, the essay assignment has to be either reformulated or given more time and credits. CONCLUDING REMARKS One important aim with the course was to contribute to the formation of Colour and light as a coherent field of knowledge. We can conclude that the interdisciplinary approach and the diverse backgrounds of participants and lecturers have favoured an interaction between fields of expertise and, more concretely, between people. All participants now have a broader understanding of issues concerning colour and light, and they have also got an interdisciplinary network for future work and collaboration. When looking at the concrete realization of the course, we can conclude that it included too much of scheduled work and too few opportunities for the participants to share and discuss each other s work. Also, more time should have been allotted to free interaction in workshops, thus making better use of the available laboratories. At the same time, all themes were considered valuable by the participants, and the course would loose some of its interdisciplinary character if some of its themes were excluded. Thus we have an equation that will be difficult to solve without extending the course time. All this will be considered in the planning of the next course, which we hope to give in

14 REFERENCES Billger, M. (1999). Colour in Enclosed Space. Göteborg, Dep. of Building Design, Chalmers University of Technology. Fridell Anter, K. (1996). Nature s colour palette. Inherent colours of vegetation, stones and ground. Stockholm, Scandinavian Colour Institute. Fridell Anter, K. (2000). What colour is the red house? Perceived colour of painted facades. Stockholm, Architecture, Royal Institute of Technology. Fridell Anter, K. (2012). Light and Colour: Concepts and their use. In: Colour and Light - Concepts and Confusions. H. Arnkil, Ed. Helsinki, Aalto University School of Arts, Architecture and Design. Fridell Anter, K. (2013). Spatial interaction between light and colour. An overview over current international research. In: Nordic Light & Colour B. Matusiak & K. Fridell Anter, Eds. Trondheim, Faculty of Architecture, NTNU. Fridell Anter, K. & K. Enberg (1997). Utvändig färgsättning. Förutsättningar, arbetssätt, exempel. Stockholm, Byggforskningsrådet. Fridell Anter, K. & Å. Svedmyr (1996). Colour scales of traditional pigments for external painting. Stockholm, Scandinavian Colour Institute. Govén, T., T. Laike, P. Raynham & E. Sansal (2010). The Influence of Ambient Lighting on Pupils in Classrooms - Considering Visual, Biological and Emotional Aspects as well as Use of Energy. Proceedings of CIE 2010 Lighting Quality and Energy Efficiency Vienna Austria Hård, A., L. Sivik & G. Tonnquist (1996). NCS Natural Color System - from Concepts to Research and Applications. Color Research and Application 21: Häggström, C. (2009). Visual distinction between colour and shape - a functional explanation applying camouflage concepts in analysis of colourdesign effects on experimental relieves. In: Proceedings of the 11th Congress of the International Colour Association (AIC 2009). D. Smith, P. Green-Armytage, M. A. Pope & N. Harkness, Eds. Sydney, Colour Society of Australia (CD). Klarén, U. (2012). Natural Experiences and Physical Abstractions. On epistemology of colour and light. In: Colour and Light - Concepts and Confusions. H. Arnkil, Ed. Helsinki, Aalto University School of Arts, Architecture and Design. Klarén, U. (2013). PERCIFAL: Visual analysis of space, light and colour. Stockholm, SYN-TES report 2E. Matusiak, B. (1998) Daylighting in linear atrium buildings at high latitudes. Norwegian University of Science and Technology, Faculty of architecture, Trondheim Matusiak, B. (2005) Luminous environment in atria at high latitudes Lighting, art & science for international designers, Volume 25, No 2. Svensk Standard (1997). Färgbeteckningssystem SS Stockholm, SIS. Valberg, A. (2005). Light Vision Color. Chichester (USA), John Wiley & Sons. Wijk, H. (1998). Colour perception in old age. Göteborg, Department of Geriatric Medicine, Vasa Hospital. 12

15 NORDIC LIGHT & COLOUR SPATIAL INTERACTION BETWEEN LIGHT AND COLOUR AN OVERVIEW OVER CURRENT INTERNATIONAL RESEARCH Karin Fridell Anter ABSTRACT This research overview is based on a large number of international publications, journals and conferences, mainly from the period It introduces and discusses occurring research themes that deal with colour or light. Research dealing with the spatial interaction between colour and light is presented in some more detail. The survey shows that neither colour nor light are any large issues in international research on architecture and design. Also when it comes to research that explicitly investigates colour and/or light, relatively little interest is paid to their spatial interaction. However, the interest for this field of research has increased during the last few years. 13

16 Introduction This research overview was carried out as part of the interdisciplinary Nordic research project SYN-TES. Human colour and light synthesis: Towards a coherent field of knowledge. The project was based at University College of Arts, Crafts and Design (Konstfack) in Stockholm and included experts representing several disciplines from six Nordic Universities, and from four leading companies dealing with colour and/or light issues. For full project publication see Scope and method The aim of the research overview is to present research reports and other scientific publications that explicitly deal with the spatial interaction of colour and light. In addition it presents current research themes dealing with the spatial aspects of either colour or light, or with the interaction between colour and light without considering spatial aspects. Primarily it covers work that has been published during the period , but also some older publications with special importance have been included. Literature has been surveyed and evaluated with the help from the broad multidisciplinary competence in the SYN-TES research group. To find relevant research we have gone through the following international publications (a more specified list is given later in this article). Proceedings from six conferences arranged by the AIC (International Colour Association) Proceedings from six conferences and symposia arranged by the CIE (International Commission on Illumination) Proceedings (or notes from personal attendance) from another six international conferences dealing with colour and/or light, All issues from of seventeen research journals specialised on design, architecture, colour or light. Books and other publications that we already knew about or came to know about through the proceedings and journals. For Swedish research we have started from a previously published knowledge review and bibliography dealing with light, colour and their spatial interaction (2008a; Fridell Anter 2008b). For obvious reasons it has been impossible to find, read and comment all potentially relevant literature. The references in this article give an overview over important research themes and mentions influential researchers and/or typical examples, but there is no ambition to cover everything. For research of more peripheral relevance to our topic we do not refer to specific publications or projects but only to larger volumes, theme conferences etc. Journals and organisations In international research on architecture and design, neither colour nor light are any large issues, and even less their spatial interaction. The volumes of twelve theoretical journals on design and architecture, from different parts of the world, include only a handful of articles that at all deal with colour and/or light, and those present art installations rather than research. Nevertheless, both colour and light are subjects of quite o lot of research, which is partly relevant in the contexts of architecture and design. Colour and light are, however, to a large extent treated as separate fields of knowledge, and most of the research on colour or light deals with entirely different questions than their spatial interaction. The International Commission on Illumination (CIE) is among other things responsible for formulating standards. The commission includes six divisions, where division 1 works with vision and colour (director M. Ronnier Luo) and division 3 with interior environment and lighting design (director Jennifer Veitch). The CIE conferences deal mostly with such as the characteristics of light sources, evaluation of new technology and related measuring methods. CIE also includes a large number of technical committees and publishes their reports, for example The measurement of visual appearance, edited by Mike Pointer (CIE 2006). The International Colour Association (AIC) gathers people who work with colour in many ways, including art, technology, and various academic disciplines. Its conferences deal with colour from a variety of perspectives, such as techniques for measuring colour differences, investigations on people s colour preferences, colour application in design, and the colour vision of elderly people. Every second year a researcher is given the AIC Judd award as recognition of outstanding work in the field of colour science. The most recent recipients were: 2007 Alan Robertson, colorimetry (see Ohta & Robertson 2006), 2009 Arne Valberg, biophysics (see Valberg 2005), 2011 Lucia Ronchi, visual science (see several titles in bibliography). Within AIC there are several study groups, and the Study Group for Environmental Colour Design (chair Verena M. Schindler) involves many researchers and practitioners within architecture and interior design. Ronchi (2010) summarises about 80 papers related to architecture, presented at the AIC conferences and Fridell Anter (2009) gives a general overview over approaches dealing with colour in art, design and architecture. The journal Color Research and Application is mostly orientated towards natural science and technology, but it also includes articles that discuss colour from the perspectives of such as 14

17 NORDIC LIGHT & COLOUR art history, perception psychology or design theory. The digital journal Colour: Design & Creativity is, as can be understood from its name, more orientated towards the aesthetic and experience creating use of colour. From 2012 it has been taken over by AIC and its new name is Journal of the International Colour Association. Journals such as Lighting research and technology, Leukos and Journal of Light & Visual Environment deal with light issues mainly from the viewpoint of illumination technology, but also include articles on design and visual experience. In recent years there have been some international conferences that have explicitly focused on both colour and light (Zennaro 2010; Schindler & Cuber 2011), and there have also been published books in several languages, with both colour and light in their titles (Valberg 2005; Fridell Anter 2006; Hårleman 2007; Zennaro et al. 2010; Bachmann 2011). Research themes dealing with colour or light Books, articles or conference presentations that deal with both colour and light only seldom discuss their spatial interaction. Instead some other themes are prevalent: - Physiological and psychological aspects of colour and light perception. - The colour rendering properties of light sources - The non-visual effects of light - Artistic work that uses coloured light - Description and/or analysis of how colour and/or light have been used in specific architectural contexts. The rapid development within neurological science has led to an increased interest for research on the visual system as such. Current research treats the basic physiological foundations for human perception of colour, light, visual contrasts and space. Starting from this, in combination with photometry and colorimetry, scientists search for patterns that can enhance the understanding of our perceptual abilities and their preconditions, possibilities and limitations (Valberg 2005; Ronchi 2007b; Ronchi 2007a). The colour rendering properties of light sources has become an important field of research during the last few years. There have been international agreements to decrease the use of traditional incandescent light bulbs in favour of new light sources that use less energy. The human visual sense, and thus our colour vision, has developed during millions of years under sunlight, and like the sun, the incandescent lamps emit radiation including all those wavelengths that can evoke visual perception. Energy lamps and light emitting diodes (LED) can, instead, be constructed to fulfil specified demands in an optimal way, and their radiation can be dominated by certain wavelengths whereas others are almost or totally missing. Thus it is essential to understand how the chosen wavelength combination affects what we see and what other effects it has on human beings. The technological innovations have drawn the attention to already known weaknesses in the methods for determining colour rendering properties in a way that enables comparisons between light sources of different types. Many published studies deal with the perception of coloured surfaces under the new light sources. There have also been several attempts to find colour rendering measurements that meet the new situation better than the CRI (Ra) that uses incandescent light as a reference. Within CIE, the technical committee 1:69 has worked with the issue of colour rendering but has not been able to agree on a suggestion for new criteria and measuring methods (Davies 2011). The CRI (Ra) is a technologically based measurement that is primarily used within the light source industry and in the planning of illumination. The issue of light s importance for colour perception and experience has also been investigated through visual observations, often with methods belonging to the fields of art or design. Combinations of light sources, pigments and dyeing substances have been tested to give such effects that are wanted in specific situations. Such studies sometimes include the ambitions to use metameric effects in creative ways. One large field of research deals with what is called the nonvisual effects of light. The wavelength composition of radiation affects people s health and daily rhythm in ways that are not necessarily tied to the visual qualities of light. Within CIE, division 6 (director Ann Webb) works with photobiology and photochemistry and has published a lot of studies and reports. Rikard Küller, late professor at the unit of environmental psychology at Lund University, Sweden, is one of the authors of an extensive bibliography over this research field (Küller & Küller 2001). Also see Govén et al and Küller The possibility to provide illumination throughout all 24 hours has had profound influence on culture and society, and the new options to design light for specific effects open for effects that are yet to be fully understood. These issues are discussed from ethnological and sociological perspectives in e.g. Garnert 1993, Brox 2003 and Barbara The light emitting diodes offer completely new possibilities to create differently coloured light, and this is used in both exterior and interior contexts. Consequently new questions arise: 15

18 What are the biological and emotional effects of coloured light on human beings, and how is it evaluated and appreciated? This type of research often deals with relatively narrow questions, such as the experience of tree illumination with different colours or the appropriate colour of light for a dinner table. Diodes with different colours are used for art installations and for so called media facades, where complete facade surfaces serve as huge screens. Those conference papers and articles that treat such phenomena most often have the character of describing presentations of installations made by the author or others, and a critical debate or analysis is found only rarely. For a number of examples see Porter & Mikellides 2009 p and the regularly published PLD Magazine. Also in the field of design and pictorial art it is most common to describe and discuss the use and effects of colour and light in the single work, without the ambition to reach conclusions of general validity. More methodical art oriented research involving colour and light deals with such as the interaction between pictorial art and illumination, and the possibilities to recreate lost paintings with the help of coloured light. At Zürich University of the Arts (ZHdK), a pedagogical and artistic research project has explored the possibilities of coloured light in interactive demonstrations of different colour phenomena, but in spite of the ambition to create new knowledge on the relationship between colour and light, the project does not include light s interaction with coloured surfaces (Bachmann 2011). Research on colour and/or light in directly architectural contexts is not common. When it occurs, it most often deals with the colouring of specific buildings, towns or time periods. Sometimes it includes also illumination and the use of daylight. The perspective is most often that of architectural history or building conservation, and the interaction between colour and light is most often not analysed. The AIC conference in Stockholm 2008 presented and discussed several examples of the colouring of urban spaces, exteriors and interiors. Also see Porter & Mikellides 2009; Boeri 2010; Kjellström 2009; Serra Lluch 2010 and Ferring Colour and the third dimension Shape and space are experienced through simultaneous perception of the colours of surfaces and of the direction and character of light. In everyday life we can most often, instantly and without reflection, draw correct conclusions about the three dimensional world around us. The strivings to understand colour as a visual phenomenon has, however, so far dealt mostly with simplified two dimensional contexts. One field of such research deals with what is called visual illusions, and the AIC has a study group on visual illusions, lead by Osvaldo da Pos. Several studies are presented in the proceedings from the AIC congress The relevance of two dimensional colour studies for architecture and other spatial contexts is discussed in Fridell Anter & Billger Recent research has increasingly dealt with colour in complex situations and realistic spatial contexts, as well as its interaction with light. This has given new insights, showing that the learnings from flat colour studies on such as visual illusions, simultaneous contrast or assimilation phenomena seldom are valid in three dimensional space (Olsson 2009; Klarén & Fridell Anter 2011; Fridell Anter & Klarén 2009b;Fridell Anter & Klarén 2009a; Klarén & Fridell Anter 2009; Mizokami & Yaguchi 2010). A few studies have also dealt with the role of colours and chromatic contrasts for the perception of shape (Akizuki & Inoue 2009). A pioneer within systematic three dimensional colour studies is the American artist Lois Swirnoff (2003). Also many other artists have used their art for investigating the relationships between experiences of light, colour, shape and space, and a handful of them have presented their findings in a way that can contribute to a systematic formulation of knowledge (Wessel et al. 2008; Häggström 2009; Moorhouse 2009; Häggström 2010 and some of the artists presented in Bachmann 2011). Galen Minah, professor of architecture at University of Washington, has used Lois Swirnoff s methods and analysed how buildings and other coloured elements are visually grouped when we observe landscapes and urban views (Minah 2001). He and other researchers have also investigated haw the perceived colour of buildings is influenced by viewing distance and weather conditions, and developed methods for measuring and analysing this (Minah 1997; Fridell Anter 2000; Pernão 2011). The colour of an object can have different modes of appearance (Katz 1935), that partly depend on the refraction and reflection of radiation. Recently, some research has been presented that investigate such as the volume colours of glass or liquids, and the colour of materials with transparent or translucent surfaces such as glazed ceramics. In such studies of colours that do not only belong to the surface of objects, the three dimensional interaction between light and colour is investigated on the detailed level. The AIC conference 2008 included a trans-disciplinary session called Aspects of materiality, and also at the AIC conference 2011 several contributions analysed the relationship between colour perception, surface structure and mode of appearance. See also Caivano et al and Svedmyr

19 NORDIC LIGHT & COLOUR Light and colour in rooms When it comes to interior rooms, there is research on how daylight reaches into the room under different preconditions and what this means for such as light level and glare (Boyce et al. 2003; Kim et al. 2007; Amorim et al. 2011; Mardaljevic et al. 2011; Pellegrino et al. 2011). Work on daylight in rooms is being done within CIE technical committees TC 3-47 and Some research has investigated how the experience of room atmosphere is affected by the light (Vogels et al. 2009). One approach has started from Katz (1935) and Gilchrist et al. (1999) and discussed the light experience in the room in terms of the colours modes of appearance (Yamaguchi & Shinoda 2007; Yoshizawa 2007). There have also been studies on how the perceived form, size and proportions of the room is affected by the form and placement of windows and the subsequent amount of daylight (Matusiak 2004; Matusiak 2006; Matusiak & Sudbø 2008), and on the effects on room perception by the direction and distribution of artificial light (Wänström Lindh 2010). There are also studies on how different illumination solutions are perceived by people with visual impairment (Matusiak et al. 2009) and how illumination should be made in rooms for different activities such as offices (Boyce 2006; Veitch et al. 2008; Kronqvist 2010; Veitch et al. 2010; Galasiu & Veitch 2008), classrooms (Govén et al. 2010) or the diverse localities in hospitals (Pechacek et al. 2008; Tannöver et al. 2008; Stidsen et al. 2010). Fotios & Houser (2007) present and evaluate a number of studies on the relationship between photometric variables like luminance and illuminance, and the experience of light level or room lightness. There have also been studies on how different illumination design influences the spatial experience in an otherwise dark exterior environment (Raynham 2007; Johansson et al. 2011; Wänström Lindh 2011). When the colours of rooms or facades are discussed it is often in the form of preference surveys that cannot claim to give results of general validity. Two typical examples of such investigations deal with Turkish school children s preferences for wall colours in class rooms (Basoglu 2006) and Japanese home owners preferences for facade colours (Yamamoto et al. 2008). There is, however, also research that raises questions on the reasons or underlying patterns of such preferences (Janssens & Küller 2008). Other studies investigate how room colours effect productivity (Kwallek et al. 2007), how colour design can support or obstruct the spatial understanding of persons with visual or cognitive impairments (Wijk 2006; Häggström 2011) and what effects room colours have on people s hormone secretion, heart frequency and other biological functions (Küller et al. 2006; Küller et al. 2009). Only few studies deal with the interaction between light and colour in built spaces. Monica Billger (1999; 2006) has carried out a pioneer work on how perceived colours and experienced space depends on the illumination, and she has also developed methods and concepts for identification and comparison of colour perception under different conditions. Karin Fridell Anter (2000) has made similar studies on the interaction between facade colours and daylight of different character. Other researchers have investigated how the experience of colours and space can vary in rooms with daylight from different compass directions (Hårleman 2006; 2007), in rooms with different types of glazing (Dubois et al. 2007; Pineault & Dubois 2008; Pineault et al. 2008) and in rooms with differently coloured artificial light (Vogels 2008). Also the relationship between the colour temperature of light and the preferences for wall colour has been studied (Manav et al. 2007). Attempts have been made to understand the principles behind the architecture of past times through analyses of how colour and light were made to interact (Tantcheva 2010; Zennaro et al. 2010; Tantcheva & Häggström 2011). Methodological pilot studies have been carried out within the recent SYN-TES project, with the aim of developing methods for investigation of complex relationships between colour, light and space (Fridell Anter 2011). The studies mentioned above have, most often, been conducted with the help of observers who have spent time in real rooms or assessed physical scale models. Also Virtual Reality simulations have been used to investigate how people experience and react upon different combinations of colour and light (van Hagen et al. 2009). The options and limitations of VR used for such purposes are discussed by Stahre (2009). Colour appearance is the label for a large field of research that uses strongly controlled tests in digital laboratories in order to develop mathematical models algorithms for the perception of colour in different spatial contexts. Work within this field is often connected to CIE s Division 1, which deals with colour, light and vision. Some examples of published studies are Gombos & Schanda 2006; Ji et al. 2006; Kutas & Bodrogi 2008; Xiao et al Discussions in the intersection between colour/light/space As has been shown above, the spatial aspects of colour and the spatial interaction between colour and light are relatively 17

20 new research areas. In addition to the specific studies, there is an ongoing discussion on the relationship between the so far separate research fields dealing with colour and light respectively. There are also discussions about the relationship between spatially oriented colour research and the results of flat colour studies. Important aspects of these discussions deal with education on colour and light and with the role of colour and light in design and planning processes. Starting from applications such as architecture and design, several researchers have pointed out the need for interdisciplinary collaboration. They have also discussed the difficulties and mistakes that can arise if you try to directly transfer results from one field to another (Hutchings & Luo 2009; Fridell Anter & Billger 2010; Van Wilgenburg 2009). One important aim of the project SYN-TES: Human colour and light synthesis was to develop and test methods for interaction between colour and light specialists from different academic disciplines and industrial branches, including the interaction between design experience and scientific analysis (Fridell Anter 2011; Fridell Anter et al. 2012a; Fridell Anter et al. 2012b; Fridell Anter et al. 2012c). One important problem in this context deals with concepts and terminology. There are numerous examples showing how one and the same word is used in different meanings (Green- Armytage 2006; Arnkil et al. 2012). At the same time, there is often a lack of established concepts for experienced qualities of light and colour. The SYN-TES research group has published the PERCIFAL method for visual analysis of light in rooms, based on concepts developed by professor Anders Liljefors (Liljefors 2005; Liljefors 2006; Arnkil et al. 2011; Klarén 2011; Matusiak et al. 2011). Other researchers analyse buildings and other architectural work as a basis for formulation of concepts regarding the use and experience of light and colour (Piscitelli 2010; Arrarte-Grau 2008). There is also some discussion on ethical aspects of the use of colour and light (Hutchings 2006; Schanda 2007) and on the role of colour and light issues in the process of planning and building design (Barrett 2010; Reisinger 2011; Fridell Anter 2012). The possibilities and limitations of digital technique to visualise colour and light is discussed from the viewpoints of different applications, such as architecture and computer games (Tonn & Donath 2006; Heldal et al. 2008; Stahre 2009; Ashdown. 2011) Education on issues regarding colour and light is, of course, central for professional understanding. In Sweden there is no established education that treats colour and light as one coherent field of knowledge (Fridell Anter 2008b app. 1), and as far as we can see the same is true in most other countries. There are a number of internationally well renowned educations in lighting design, but their curriculums include very little about colour. See for example KTH Lighting Laboratory, Stockholm, Sweden: and Lighting Research Centre, Troy, USA: To what extent, and in that case how, colour and light are included in regular education of designers and architects varies much between different places, and seems to depend largely on the interest and driving force of individuals. In international conferences and other contexts we have met several architects and teachers of architecture from different countries, who have, in different ways, expressed their frustration over the fact that this field of knowledge, so important for architecture, is not enough considered in the education of architects. See e.g. García Gil et al. 2006; Green-Armytage 2006; Mikellides 2006; Minah 2008 for reports from engaged colour pedagogues. On the post-graduate level, a number of initiatives have been taken on Nordic and international level. One example is CREATE (Colour Research for European Advanced Technology Employment), which with support from the European Union has built a network with focus on colour education ( uwe.ac.uk/, Parraman & Rizzi 2008). Another example is the doctorate course Nordic Light and Colours, which was initiated within the SYN-TES project and given at NTNU, Trondheim, in April 2012, with support from NordForsk ( bff/lightandcolour). Both these initiatives must, however, so far be considered temporary, in the absence of economic and organisational stability. Conclusions: Existing knowledge and required research The survey of international research literature shows that relatively little research has dealt with the spatial interaction between colour and light, but also that the interest for this field of research has increased during the last few years. In spite of the fact that two large conferences in explicitly addressed colour and light, most contributions there still dealt with either colour or light (Zennaro 2010; Schindler & Cuber 2011). When it comes to research that explicitly deals with both these aspects of visual experience, Nordic researchers have a strong standing within the international research community. Thus we can conclude that the inter-disciplinary collaboration that characterises the SYN-TES research project is very rare, seen in an international context. There is a great need for further research on the spatial interaction between light and colour. Initially this requires a development of methods that can include several aspects of 18

21 NORDIC LIGHT & COLOUR experience at the same time, and that can be used in contexts that cannot be directed or controlled as in regular experimental studies. For the development of the field of knowledge, it is necessary that contacts and collaborations between different academic disciplines and industrial branches are deepened and consolidated. To achieve this, it is essential that different professions learn something about each other s specific language and way of thinking. Multi-disciplinary and multi-professional education on colour light space as a coherent field of knowledge should be given high priority. Introductory elements regarding this field should be part of a number of educations on different levels, dealing with such as architecture, design, lighting planning and painting. To achieve a critical mass of sufficiently initiated people there is also a great need for more coherent education, for example colour and light design on advanced level (master and doctorate) for students who have already a relevant basic education. Sources journals and conference proceedings Research journals , without explicit focus on colour or light (None of these journals had any article about spatial interaction between colour and light) - Swedish Design Research Journal - Nordic Journal of Architectural Research - Journal of Design Research (JDR) - International Journal of Design - Design Research Journal - Point. Art and design research journal - Design Studies) - Journal of Architectural and Planning Research - International Journal of Architectural Research - arq: Architectural Research Quarterly - Architectural Design Research - Architectural Science Review Research journals with explicit focus on colour - Color Research and Application - Colour Design and Creativity Research journals with explicit focus on light - Lighting research and technology - Journal of Light & Visual Environment - LEUKOS the Journal of the Illuminating Engineering Society of North America Proceedings from conferences arranged by AIC (International Colour Association) Colour in Culture and Colour in Fashion (Johannesburg, South Africa) Colour Science for Industry (Hangzhou, China) Colour Effects and Affects (Stockholm, Sweden) AIC 11:th congress (Sydney, Australia) Colour and Food from the Farm to the Table (Mar del Plata, Argentina) Interaction of Colour and Light in the Arts and Sciences (Zürich, Switzerland) Proceedings from conferences and symposia arranged by CIE (International Commission on Illumination) nd CIE Expert Symposium on Light and Health (Ottawa, Canada) CIE Expert Symposium on Visual Appearance (Paris, France) CIE Session and World Conference (Beijing, China) nd CIE Expert Symposium on Appearance: When Appearance meats Lighting (Gent, Belgium) Lighting Qualitiy and Energy Efficiency (Wien, Austria) CIE Session and World Conference (Sun City, South Afrika) Proceedings (or notes from personal attendence) from other relevant conferences Experiencing Light, International Conference on the Effects of Light on Wellbeing (arr.eindhoven University of Technology, the Netherlands) Seminário Internacional: Cor Arquitectura e Design (arr. Universidade Luisíada de Lisboa, Lisbon, Portugal) Colour and light in architecture (arr. Università Iuav di Venezia, Venice, Italy) -2009, 2010 and Ceebel - Centrum för energieffektiv belysning (Center for energy efficient illumination) Programme conferences in Katrineholm, Sweden. 19

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26 Serra Lluch, J. (2010). La versatilidad del color en la composición de la arquitectura contemporánea europea: contexto artistico, estrategias plásticas e intenciones. Valencia, Universidad Politechnica de Valencia. Stahre, B. (2009). Defining Reality in Virtual Reality: Exploring Visual Appearance and Spatial Experience Focusing on Colour. Gothenburg, Chalmers University of Technology, Dep. of Architecture (Diss). Stidsen, L., P. H. Kirkegaard, A. M. Fisker & J. Sabra (2010). Design Proposal for Pleasurable Light Atmosphere in Hospital Wards. In: Colour and Light in Architecture. P. Zennaro, Ed. Verona (Italy), Knemesi. Svedmyr, Å. (2002). Den målade fasadytans materialitet. Stockholm, Arkitektur/Formlära, KTH. Swirnoff, L. (2003). Dimensional Color, second edition. New York & London, W.W. Norton & Company. Tannöver, S., A. Düzgünes & S. Yilmazer (2008). A Critical Analysis of Sunlight Patches in Patient Rooms via Simulation. Architectural Science Review 51(3): Tonn, C. & D. Donath (2006). Color, Material and Light in the Design Process - A software concept. Proceedings of the Joint International Conference on Computing and Decision Making in Civil and Building Engineering (ICCCBE), Montréal, Canada. June 14-16, 2006: Valberg, A. (2005). Light Vision Color. Chichester (USA), John Wiley & Sons. van Hagen, M., M. Galetzka, A. Pruyn & J. Peters (2009). Effects of Colour and Light on Customer Experience and Time Perception at a Virtual Railway Station.. In: Proceedings EXPERIENCING LIGHT International Conference on the Effects of Light on Wellbeing. Y. A. W. de Kort, I. W. A., I. M. L. C. Vogelset al, Eds. Eindhoven, Eindhoven University of Technology: Van Wilgenburg, C. (2009). The Unifying Vision of Colour. In: Proceedings of 11th congress of the International Colour Association, Sydney D. Smith, P. Green-Armytage, M. A. Pope & N. Harkness, Eds. Veitch, J. A., G. R. Newsham, P. R. Boyce & C. C. Jones (2008). Lighting appraisal, well-being and performance in open-plan offices: A linked mechanisms approach. Lighting Research and Technology 40: Veitch, J. A., G. R. Newsham, C. C. Jones, C. D. Arsenault & S. Mancini (2010). High- quality lighting: Energy-efficiency that enhances employee well-being. Proceedings of CIE 2010 Lighting Quality and Energy Efficiency Vienna Austria Wessel, G., L. Högman, U. Klarén & R. Lindhé (2008). Slutrapport: Visuella Världar Stockholm konstfack.diva-portal.org/smash/get/diva2:399802/fulltext01. Wijk, H. (2006). Färg som stöd och stimulans i vårdmiljön. In: Forskare och praktiker om FÄRG LJUS RUM. K. Fridell Anter, Ed. Stockholm, Formas: Vogels, I. (2008). Effect of coloured light on atmosphere perception. Proceedings from AIC Interim Meeting Colour - Effects and Affects, Stockholm June 2008, Research paper 060. Vogels, I., D. Sekulovski, R. Clout & R. Moors (2009). A quantitative study on the impact of light on the atmosphere of an environment. In: Lux Europa 2009; 11th european lighting congress, Istanbul, September A. K. Yener & L. D. Oztürk, Eds. Istanbul, Turkish national committee on illumination: Wänström Lindh, U. (2010). Spatial Interpretations in Relations to Designer Intentions: A Combined Strategies Study in an Auditorium with Variable Lighting. In: Colour and Light in Architecture. P. Zennaro, Ed. Verona (Italy), Knemesi: Wänström Lindh, U. (2011). Lighting design research in public space: A holistic approach to a complex reality. The 27:th session of the CIE International conference July Sun City, South Africa, CIE: Xiao, K., M. R. Luo, C. Li & G. Hong (2010). Colour Appearance of Room Colours. Color Research and Application 35: Yamaguchi, H. & H. Shinoda (2007). Evaluation of space brightness based on the border luminance of colour appearance mode. In: 26th session of the CIE. Beijing 4 July 11 July Proceedings. CIE, Ed. Vienna, CIE: D Yamamoto, S., S. Inoue, M. Ota & K. Nishikawa (2008). Colour preferences for facades of detached houses in Japan. Proceedings from AIC Interim Meeting Colour - Effects and Affects, Stockholm June 2008, web publication Research paper 121. Yoshizawa, N. (2007). Light phenomena in architecture and ther relation to the illumination and texture. In: 26th session of the CIE. Beijing 4 July 11 July Proceedings. CIE, Ed. Venna, CIE: D Zennaro, P., Ed. (2010). Colour and Light in Architecture. Verona, Knemesi. Zennaro, P., K. Gasparini & A. Premier, Eds. (2010). Colore e luce in architettura: Fra antico e contemporaneo. Vicenza, Knemesi. 24

27 NORDIC LIGHT & COLOUR NORDIC DAYLIGHT Barbara Szybinska Matusiak ABSTRACT The purpose of this study was to examine if the daylight in Nordic countries is significantly different from daylight in other regions. Approaches used in this study stretch from the analysis of painter s thoughts on the colour and light of a place to the examination of solar diagrams, the calculation of solar angle and the examination of climatic data. The conclusion of the study is that daylight in Nordic countries is significantly different. The reasons are: a very low mean solar angle during the year, long periods of twilight and a high frequency of overcast sky. Those geographical and climatic facts have a strong impact on the illuminance level on the ground, the colour of daylight and the modelling of landscape, buildings, terrain and peoples. A series of specific phenomena may be observed in Nordic countries, as e.g. white nights, self-luminous objects and a heavy cloud coat. 25

28 26 Figure 1. Cloud coat photographed just before and just after sunset in Trondheim.

29 NORDIC LIGHT & COLOUR Introduction Daylight is important for humans everywhere on the globe, but it may be perceived differently in different places and regions. The Nordic countries are special because of their closeness to the North Pole; most large towns in Nordic countries are situated closely to, or north of, 60 N. Similar qualities of daylight are hardly to be perceived on the Southern Hemisphere, since the world s southernmost permanently inhabited community, Puerto Toro, is situated at S. This fact underscores the uniqueness of the Nordic countries location. In this essay we will look more closely at the effects of this specific location on the quality of daylight and twilight. Sunset Who does not enjoy looking at the sun slowly gliding down toward the horizon and changing appearance from the hazardous and glary giant light source, to a yellow-orange disk that is not harmful nor glary any more, but gorgeous. The awareness about its inevitable disappearance makes it even more beautiful. The warm colour of the sunset sunlight is often scattered in the atmosphere painting the sky and the clouds in warm yellow-reddish colours. Sometimes the low and heavy clouds are illuminated from beneath, giving an impression of a heavy coat hanging over the earth, see figure 1. Slowly and inevitable the sun is moving down (and to the right) and gradually disappears beneath the horizon. Instantly the direct radiation is gone, but the coloured clouds are still there, witnessing about the act that has ended just moments ago, see figure 2. A beautiful sunset is possible to observe at each place on Earth and on each clear day of the year. Only the time of the sunset changes, e.g. the sunset in Oslo on the 21st December occurs at 15:12, while on the 21st of June it occurs at 22:43. The respective times for Cairo are: 16:59 and 19:59. The sunset act has also different tempo in different places and on different days. On the Northern Hemisphere the difference in the sun s movement speed of the sun, as observed on the sky, is most clear during the summer. In the far north the sun seems to move slowly, whereas it is the most rapid close to Equator. On the 21st of June it takes 29 min for the sun to move from the 5 elevation angle to 0 (horizon) in Cairo, while in Oslo it takes 1 hour and 7 min. Additionally, the direction of the sun movement is much more horizontal in Oslo, see figure 3. There are a few more phenomena appearing sporadically on the sky that we may observe and enjoy, the most known ones being the rainbow and the rain fog. Additionally, similar cloud tapes and shapes can be observed on the sky at most places on Earth, i.e. stratus clouds with horizontal layering and a uniform base, cumulus clouds growing upwards and taking various exuberated shapes and cirrus clouds characterized by thin, wispy strands, associated with curling locks of hair. If there are so many similarities, is the perception of natural light at different places and in different regions the same? Painters on the colour and light of a place To find an answer to this question, let us look at the heritage of fine artists, the group of people probably most sensitive to changes of natural light and colour. The British painter, Joseph Mallord William Turner ( ) (Bockemühl 2011), claimed that each place has its special natural light and its special colours. During his life Turner made as many as forty sketching tours ( ) across Britain and Europe, mostly in France, Switzerland and Italy, studying light and registering characteristic colours for the respective places in Europe. The results of his colour registrations are shown at the Tate Britain gallery in London (Tate Britain 2000). The impressionist painters were extremely aware of the diurnal and seasonal changes of light and colour at various places. One of their main objectives was the accurate depiction of light as perceived at a certain place at a certain moment. They were recreating the impression of the moment, which was not possible to capture by photography or to measure with physical instruments. The impressions were connected to the place, its light and the moment. Nordic painters who were active in the last two decades of the nineteenth century were aware of the uniqueness of natural light in Nordic countries. Some beautiful examples of paintings from this period are presented in the book Nordic light, interpretations in architecture (Sørensen 2011). Jan Garnert in the essay On the cultural history of Nordic light and lighting (Garnert 2011) underscores the admiration that Nordic artists had for the white nights with a warm and nearly horizontal sunlight that models people and objects in a unique manner. He described among others a work of the Swedish painter Anders Zorn, see figure 4, where the red colour of sunlight is evidently exposed using red-dish paint. In Juhani Pallasmaas essay The ambience of Nordic light (Pallasmaa 2011) another specific daylight scenario is presented, namely the diffuse and white light that occurs during the winter, see figure 5. As seen in Washing on ice by Pekka Halonen, from 1900, the light is soft, untouchable and independent on orientation; people and subjects are illuminated evenly and equally from all directions; the shapes are lacking depth; the 27

30 28 Figure 2. Sunset in Trondheim

31 NORDIC LIGHT & COLOUR Figure 3. The sun diagram for Oslo and Cairo generated in relation to an observer standing at the centre. The horizon is represented by the largest circle. colours are subdued, and there is no sparkling, no reflections and no shadows. Since the fine artists were convinced about uniqueness of Nordic light, maybe we may find some objective data that can support this point of view. The position of the sun Let us reflect on one of the most important parameters, which is the position of the sun on the sky, as is visible in the Nordic countries. It may be observed that three capitals and other large towns in northern Europe have latitudes close to 60, see table 1. Table 1. Latitudes for large Nordic cities situated closely to 60 N. Even a squat look at the sun diagram for one of those cities, e.g. Oslo, and the sun diagram for, say, Cairo, will help us find the most fundamental difference between daylight in the North and in the South, i.e. the prevailing height of the sun over the horizon. The sun moves straight up after sunrise in Cairo. In Oslo the movement is more horizontal; the elevation angle of the sun increases slowly over many hours and never reaches the area around the zenith. The highest position of the sun during the year in Oslo is 53,53, the elevation angle at noon at the equinox is only 30,52, while the two respective angles for Cairo are 83,37 and 60,33. Timing of the solar elevation angle Another interesting aspect is connected to time. Since the position of the sun in Nordic countries is very low, the sun is near the horizon considerably longer than in countries situated at lower latitudes as e.g. Cairo, N. The very interesting question is how long can we expect the sun to be e.g. between 0 and 10 above the horizon? The calculations of the percentage of daytime occurring during the first part of the year when the elevation angle of the sun is in intervals - (0-10 ), (10-30 ) and (over 30 ) - were made with the help of the Solar Beam software (Solar Beam 2013) for Trondheim: ), see figure 6 and 7. The results are presented also in table 2. 29

32 Figure 4. Anders Zorn, Midnight, Figure 5. Pekka Halonen, Washing on ice, 1900.

33 NORDIC LIGHT & COLOUR The highest elevation angle of the sun during the shortest day of the year, 21st of December, is only 3,35. In the period from the 21st of December to the beginning of February the elevation angle of the sun will never reach 10, this occurs first on the 3rd of February. After this day the number of hours when the sun is over 10 increases rapidly on a daily basis, but we have to wait until the 30th of March to observe the sun reaching the 30 elevation angle. The highest position of the sun in Trondheim is 50,01. There are only four days during the year, 19th, 20th, 21st and 22nd of June, when the elevation angle of the sun is higher than 50 ; at 21st of June it lasts for 12 minutes. Table 2. The time duration in hours when the sun is in the three elevation angle intervals, calculated monthly for the first part of the year in Trondheim. The results are striking: the percentage of time when the sun is between 0 and 10 is 35%. This means that for more than 1/3 of the whole daytime during the year we may expect a nearly horizontal light from the sun. The time when the sun is in the 0-10 angle interval is actually much longer than the time when it is over 30 (26%). Twilight Since the sun stays for that long time just over the horizon, it may also stay for a long time just beneath the horizon. To examine this, the twilight time was calculated! The twilight is defined as a condition where the sun is no more than 6 beneath the horizon. The total twilight duration, 430 h for ½ year, i.e. 860 h a year, is a long time. Twilight makes 19% of the night-time during the year (the length of the daytime and the night-time in a year is equal). The twilight duration is longest during the summer months. During the four weeks period closest to the summer solstice (21st of June) the twilight is strong enough to illuminate landscape and people quite well, even daytime activities, such as reading, are still possible without artificial light on a clear night. There is no really dark time during the whole night; the white night is a fact. White nights should not be mixed up with midnight sun that occurs only at places north of the Arctic Circle N. The midnight sun does not occur in the capitals of Nordic countries and other settled areas situated about 60 N. Duration of sunny skies We should not forget that availability of the sunlight is also strongly dependent on the cloud cover. Let us look at the frequency of sunny skies. For this purpose four maps were generated with the help of the Satel-Light (Satel-Light 2013), see figure 8 and 9. The frequency of sunny skies during the year in Europe north for Alps is rather low (30-40%), the British Islands receive the least sunlight. In the Nordic region covered by the satellite and shown on the map, the highest frequencies of sunny skies may be found at the Baltic See (40-45%), the lowest in the Norwegian mountains (20-25%), see figure 8. A large difference may be observed between different seasons and different months of the year. Generally, the highest frequency of sunny skies occurs in spring, the lowest in winter, figure 9. Special features of daylight in Nordic region The analysis made so far shows the typical features of daylight in the Nordic countries: 1. Dominating low solar elevation angle during the year 2. Long periods of twilight and white nights in the time period close to summer solstice, midnight sun at places north of the Arctic Circle 3. Rather low frequency of sunny skies during the year, especially during winter What are the consequences of the dominating low solar elevation and low occurrence of sunny skies? When solar elevation angle is low, the sunlight accessibility is obviously low, in buildings and outside, especially in mountain regions and areas with undulating terrain. Even if the sunlight is present, it has much lower luminous flux than in southernmost regions, it is not perceived as dangerously strong, both for the people and for the natural environment. The modelling of terrain and objects is sparse and gently. The low position of the sun contributes to frequent occurrence of solar glare, i.e. an experience of the presence of the sun in the visual field of a subject. The low sun is even more annoying than a high sun, since the direction of view is very often horizontal, at least outdoors. People living in Nordic region are annoyed by solar glare quite often; they worked out an intuitive, unconscious method for tackle the solar glare, e.g. by turning the body and/or visual object to a more comfortable position. Also simple sun shading methods have been developed for usage in buildings, often a 31

34 Figure 7. Timing of solar elevation intervals in Trondheim in the period 21st Dec. 21st June. The intervals are 0-10, and The white line represents daytime, i.e. from sunrise to sunset. Figure 6. The sun diagram for Trondheim generated using the Solar Beam software. The area of the diagram representing 0-10 elevation angles of the sun is marked with red and the area representing elevation angles over 30 with yellow. Figure 8. The frequency of sunny skies during the year: Nordic region left, Europe to the right. 32

35 NORDIC LIGHT & COLOUR mixture of textiles and venetian blinds, figure 11. The venetian blinds are used when the sun is a source of overheating or glare, the slats may be positioned to nearly completely reject the light protecting users against the excessive radiation, but they may also be adjusted to the cut-off position allowing penetration of light from the ground and the low part of the sky while just rejecting the sunlight. The textile curtains are used when the sky is a little too bright. Many other configurations are possible also. The solar glare from low sun occurs in Nordic region from nearly all sky directions, from the south in winter, from the east and west in spring/autumn and even from the north-east and north-west in summer. It may occur at very different time of the day: at the middle of the day in winter, at the morning and evening in spring/autumn. In summer it may happen even during the night time. When solar elevation angle is low the effect of reflected sunlight is much stronger, since the reflectance of specular surfaces increases with the incidence angle of light. It is nearly similar for water, ice and snow, figure 12. The strong effect of reflected light may be perceived negatively (glare) or positively (larger light flux) for daylighting of interiors. Sometimes the daylight may enter buildings more from below than from the sky. Such effects happen when the sunlight reflected from the ground makes stronger illumination than the whole sky that may be heavy overcast at the moment. When solar elevation angle is low the way of solar radiation through the atmosphere is longer resulting with the excessive scattering of light, consequently, the mean colour temperature of sunlight during the year is lower, which means more of the (yellow-red) light, figure 13. Sometimes even the purple colour may appear on the sky when the blue skylight is mixed with the reddish sunset sunlight, figure 14. When solar elevation angle is low the sunlight direction has a very strong impact on the modelling of landscape and buildings. The vertical surfaces, mostly building facades, are sometimes lighted very strongly by nearly horizontal sunlight from a side and appear as brighter than both the ground and the sky. Looking at the picture in figure 15 we may ask how the buildings are illuminated. It seems like they are self-luminous. The low occurrence of sunny skies makes us used to the gray sky. The gray sky is a prevailing condition; a form of reference. It makes us aware about the high value of the solar radiation, both for the vision and health. The human memory of an event, as described by Daniel Kahneman (Kahneman 2011), is characterized by the neglecting of time and the profound impact of top-peaks and ends of the event. Applied to remembering daylight it means that even a very short appearance of the sun at the sky that creates a nice, beautiful or a dramatic image is remembered much better than hours with the overcast sky, we just neglect the grey sky time with slightly variations of luminance, we remember the top-peaks, i.e. the very special images often created by the sunlight penetrating through the cloud cover or illuminating it from beneath. We remember the image best in its full strength, its most expressive variant. Conclusions The differences between daylight in the Nordic region and other regions have been demonstrated. The main reason is the dominating low solar elevation angle during the year and consequently the long period of twilight, as well as the low frequency of sunny skies. Those geographical and climatic facts have a strong impact at the illuminance level at the ground, at the colour of the daylight, at the modelling of landscape, buildings, terrain and people. The low sun is also a serious and changeable source of solar glare. A series of different specific phenomena may be observed in Nordic countries, as e.g. White nights, self-luminous objects and heavy cloud coat. The low frequency of sunny skies contributes to better remembering of various expressive images that appear at the sky in Nordic region as the prevailing gray sky is a neutral reference. In comparison to it, colourful sky images or images characterized by strong contrast appear as very interesting, even if they last only for a moment. 33

36 Figure 9. The frequency of sunny skies in the Nordic region: April to the left, December to the right. 34 Figure 11. Sun shading in one of the offices at the NTNUs campus.

37 NORDIC LIGHT & COLOUR Figure 10. Daylight in the Norwegian fiord. 35

38 Figure 13. Reddish sun-light in the interior during Christmas-time. Figure 14. Purple colour at the sunset sky. 36

39 NORDIC LIGHT & COLOUR Figure 12. Reflection of sunlight in water. Figure 15. Low sun in Trondheim, self-luminous buildings. 37

40 References Bockemühl, M. (2011) J.M.W. Turner, Taschen GmbH, Köln. Garnert, J. (2011). On the cultural history of Nordic light and lighting In: Nordic Light, interpretations in architecture, Denmark, Clausen Grafisk, Kahneman, D. (2011). Thinking, Fast and Slow, Farrar, Straus and Giroux, New York. Pallasmaa, J. (2011). The ambience of Nordic light In: Nordic Light, interprettations in architecture, Denmark, Clausen Grafisk, Satel-Light (2013) web-page: Solar Beam (2013) web-page: Sørensen, N., Haug P., editors (2011). Nordic Light, interpretations in architecture, Denmark, Clausen Grafisk. Tate Britain, (2013). exhibition Turner s Travels colour-and-line-room-guide/colour-and-line-6 38

41 NORDIC LIGHT & COLOUR LEVELS OF EXPERIENCING COLOUR AND LIGHT Ulf Klarén, Harald Arnkil, Karin Fridell Anter ABSTRACT Design is the art of using knowledge implicit or explicit about how humans perceive, experience, and relate to the world around. In design all senses are involved, but when dealing with colour and light we can confine ourselves to vision; designers must understand the conditions of visual perception. Human experience of colour and light has many sources; the given cultural context (conventional meanings of colour and light), the direct experience of the world around (colour and light expressions) and the basic perceptual functions (formal aspects of colour and light). There is need for distinct concepts and concise approaches to understand coherence of aesthetic and functional expressions. Design education calls for coherent and well defined structures that can be used to describe connections and distinctions between experiences of different kinds. 39

42 Background The aesthetics of colour and light play an important role in the fields of art, design and communication. Colour and light in built spaces influence our experiences and feelings, our comfort and physiological well-being. Colour and light have great impact on health and can promote visual clarity, functionality, orientation and sense of security. When designing, colouring and illuminating objects and environment (or ourselves), a general experience of a rich and complex world around is not enough. To a designer it is also necessary to have a sound knowledge of what constitutes how we experience the world both for the creative process and a critical distance. It is one thing to experience or intuitively imagine the tone of an object or a mood of a space; another thing is to be able to consciously reflect on the sources of such experiences. Professionals in the field of design must in one way or another find distinct concepts and concise approaches in order to understand coherence and causes of aesthetic expression. Such concepts and approaches are not easily found. The essence of our experiences and emotions might even be beyond the limits of (verbal) language. But, as Ludwig Wittgenstein has pointed out, even if we cannot explain them verbally they manifest themselves to the senses. They can be demonstrated and their cognitive and perceptual basis can be described (Wittgenstein 1992: 64, 122). Creativity requires conceptual means to consider conditions and nature of intuitions and experiences. And this is not only important for designers, artists and researchers. It is also highly important to technicians and politicians and, actually, to all of us. We are all responsible for how the world is designed. In design all the senses are involved, but when dealing with colour and light we can confine ourselves to vision; designers must understand the conditions of visual perception. Colour and light are only seldom integrated from the beginning in the design process in education. Traditionally colour and light in design and design education have been looked upon as something that is discussed when the design is finished; designed objects or designed spaces are thought to be coloured and illuminated afterwards. This educational choice or lack of choice is done in spite of the fact that appearance is basic in spatial design, and that colour and light are absolute conditions of appearance. This way of looking at colour and light as being subordinated and of minor importance is based on an insufficient understanding of human visual perception and on basic conceptual confusions. Academic research about colour and light is split between several disciplines. There is also technological research and development of light sources, light fittings, dyes, paints etc. carried out by industry. This division between different institutions and organisations has lead to diverging research traditions and conceptual approaches. Manufacturers and researchers often have difficulties understanding and forming opinions about each other s methods and results, although they are working with similar questions. One important aspect of this is the absence of common and generally accepted concepts. The confusion about the concept of colour is discussed in Green-Armytage (2006). The need for specifications of the concept of light is discussed in Liljefors (2006). In design education this incoherence of the field has resulted in confusion of ideas about the nature of colour and light. Colour, light and space We live in a spatial and continuously changing world. Our cognitive and perceptual systems derive their distinctive characters from this fact. Even if our perceptions are subjective, our basic spatial experiences are natural perceptual facts and functionally universal. All senses add to the experience of a spatial and changing world around, but the principal spatial sense is sight. Vision provides a coherent and continuous understanding of space. We always experience the surrounding world as three-dimensional: visual patterns that can be understood as spatial are given naturally such an interpretation in perception (Gregory 1966:147). Traditionally, research about colour has most often neglected the need of knowledge about spatial visual perception, and although colour and light are mentally inseparable in our experience of the world around, the complicated relation between colour and light experiences has not been given attention. Colour phenomena have usually been presented two-dimensionally and without intention to be spatially experienced. If they, in that way, are abstracted from their natural and simultaneous connections to light, spatial order, and cultural context, the causal relations behind colour phenomena become inconceivable and mystified. Concepts describing colour and light as integrated in a spatial whole have to be based on coherent spatial experiences. Spatial perception demands spatial relations and directions, size gradients, enclosure, etc. David Prall (1936: 39) says: You cannot make a spatial whole except with elements the very nature and being of which is spatial extension The elements must lie in an order native to their being, an order grasped by us as constituted by relation. We call structures intelligible so far we find them capable of analysis into such elements so related. Colours as such have no spatial extension. They have no formal structure except colour qualities related to other colour qualities, i.e. contrasts in lightness, whiteness, blackness, hue or chromaticness (this colour terminology refers to The Natural Colour System, NCS The Swedish standard for colour nota- 40

43 NORDIC LIGHT & COLOUR tion). If focusing on colour in spatial context, colour and light theory is given theoretical connection to our intuitive understanding of the world around and can be part of a wider field of aesthetic research and education. Colour, light and physics In the field of colour and light, visual/perceptual phenomena too often are described and analysed with the use of physically based concepts. This can give the impression that physical measurements also measure what we see. But this impression is false and it is not only a question of simplification. Using physically based concepts to describe perception of colour and light may be both misleading and incorrect. This does not, however, mean that concepts referring to abstract but measurable structures of the physical world are not useful. But they are useful only as long as they are used to describe the material world. It is, for example, necessary for paint industries and light source industries to have instruments to control and maintain physical standards of their products. We experience colours intuitively as properties belonging to the outer world. In the physical world beyond the reach of the senses the existence of colour and light can only be demonstrated indirectly by measuring spectral electromagnetic radiation with wavelengths between approximately 380 nm and 760 nm. The human eye responds to this radiation, but the rays themselves are not visible. Isaac Newton remarks that the rays, to speak properly, are not coloured. In them there is nothing else than a certain power and disposition to stir up a sensation of this or that colour (Newton 1704). It is true that experience of colour and light is dependent on electromagnetic radiation but the colour of an object are only to a certain degree dependent on spectral distribution of the radiation that it reflects. The Norwegian neurophysiologist Arne Valberg states: The reflection properties of surfaces relative to their surround are more important for colour vision than the actual spectral distribution reaching the eyes. (Valberg 2005: 266). The American philosopher C.L. Hardin concludes that there is no reason to think that there is a set of external physical properties that is the analogue of the (colours) that we experience (Hardin 1993: xii). Colour, light and adaptation The relationship between the physically measurable and vision is complicated. Our perceptual systems counterbalance physical changes in the world around. Our vision is based on a continuous adaptation, which strives to keep the colours of the surrounding world. When perceiving colours, our vision does not register the absolute intensity or the absolute spectral distribution of radiation that reaches our retina. Instead distinctions and relations are registered. Hence our visual system is developed for a continuous spectrum of light and gradual changes between different illuminations. Under these circumstances we perceive colours as more or less constant if our visual system has had time to adapt to the specific light situation. The mechanisms that make us perceive and determine the lightness of surfaces observed in different situations have been thoroughly considered by Alan Gilchrist et.al (1999). Gilchrist et al. state that it is not the luminance that determines the perceived lightness of a surface. Any luminance level can be perceived light or dark depending on context, and the surface that we perceive as white functions as an anchor for perceived lightness of all other surfaces seen simultaneously. Most often our anchor for white is defined as the surface that has the highest luminance in the visual field Highest Luminance Rule. This is, however, not true in all situations, since we also have a tendency to perceive the largest area in the field of vision as anchor for white Area rule. As long as the lightest area also is the largest, the two rules coincide, but they come into conflict if the darker one also is the largest. Then we tend to perceive the largest area as white at the same time as the smaller and lighter area also is perceived as white - a paradox that is solved by perceiving the smaller area as luminous. But even if we experience that an object has the same colour in different light we can at the same time perceive a slight tone of colour that reveals the character of light. All colours have at least a slight chromaticness and a hue. We never experience absolutely neutral achromatic colours (Fridell Anter & Klarén 2009). For nominally white surfaces this effect is more obvious than for nominally chromatic surfaces. We experience the surface as white but we understand at the same time that it is illuminated with a light of a special quality and intensity. This involves not only light coming directly from the light source, but also reflected light from surrounding surfaces. Reflection from chromatic surfaces in a room can give a hue to a nominally neutral or slightly chromatic surface, which is especially evident in nominally neutral light surfaces (Billger 1999). Klarén & Fridell Anter (2011) have shown that the lightness anchor also functions as a perceptual anchor for experience of hue. With an analogy from music theory white anchoring could be regarded as a transposition where the surface that is perceived as white is the keynote or keycolour for perception of both lightness and hue in a given light situation; the keycolour decides all relations between the colours in the field of vision. The French philosopher Merleau-Ponty (2002: 355) discusses how we experience the surrounding world in different ways depending on situation. He makes a distinction between two modes of attention: he talks about the reflective attitude and living 41

44 perception. We use the reflected attitude when we attend to and consciously compare one colour to another. In living perception colours are manifested to us in the totality of spatial relations; it is the everyday way of attending to colours. Depending on modes of attention, a nominally white surface lit by warm sunlight can be seen, with a reflective attitude, as slightly yellowish. With living perception, however, we may feel that the same surface is white; we experience intuitively that it also has independent of the accidental yellowish light a constant colour experienced beyond the perceived colour. One could call this colour constancy colour (Klarén 2012: 24). Constancy colour refers to a natural perceptual skill ; we intuitively summarize the totality of perceived visual information in a given context. We have a tendency to regard the constancy colour as the proper or real colour of the wall. Ewald Hering s concept memory colour (Gedächtnisfarbe) touches on this phenomenon, but confines it to expected colours in objects: What the layman calls the real colour of an object is a colour of the object that has become fixed, as it were, in his memory; I should like to call it the memory colour of the object (Hering 1920). Merleau- Ponty says that the real colour persists not as a seen or thought-of quality, but through a non-sensory presence. (Merleau-Ponty 2002: 356). All these colour and light interactions are what makes us perceive space visually. Normally we have no difficulty in making distinctions between what is caused by the light and what by the qualities of surfaces. The logically distributed colour variations caused by light, reflections and shadings are to our intuition natural and indispensable spatial qualities. There is a tight perceptual attunement between us and the world around. The experienced world is in ecological balance with the human environment, and the perceptual relation between the outer world and the human inner world is without hindrance. In addition to the basic perceptual processes and the direct spatial understanding of the world around, human comprehensive experience of colour and light is also related to culture. Imaginations, conceptions and ideas about the world provide a context to our sensory experiences. The American philosopher Alva Noë (2004: 1 3) remarks that adaptation is not limited to basic physiological reactions. It is both perceptual and cognitive and derives its origin from multiple sources, external as well as internal. Human experience of colour and light in the world around is related to the context as a whole. It is made up from interplay of the individual and the world on many levels. In this sense colour and light are natural but non-physical. Levels of experience It is true that we see colour and light, but what we so vividly experience is a coherent world full of life and meanings. The human experience is multidimensional and dynamic. Its totality cannot be described easily. Just like all sensory experiences, colour and light are perceived and understood on different levels: from the basic that are common to all humans to the most rapidly changing cultural trends. Figure 1 shows levels of experience - from experiences based on categorical basic perception (formal aspects of colour and light) through direct experience of the world around (colour and light expressions) to the indirect experience (conventional meanings of colour and light), imbedded in cultural expressions; history, traditions, customs, trends, scientific theories, art, poetry, etc. Categorical perception Categorical perception gives basic spatial and temporal structure to experience of the surrounding reality. It comprises the basic perception of colour, light and space, balance, verticality and horizontality, movement, etc. We perceive the surrounding world (and ourselves) in time and space, as were it, without hindrance. The world appears as an aesthetic surface (Prall 1936). We perceive patterns of colours, shapes, sounds, scents, tastes and textures as part of a spatial context. The ultimate purpose of categorical perception is to build a comprehensive mental image of the human world: A reality without well-defined borders is divided up into distinct units by our perceptual mechanism (Gärdenfors 2000: 20. Our transl.). By natural selection man has been endowed with certain perceptual and cognitive tools for survival that are basically common to us all. Categorical perception is in some respects determined genetically, but for the most part acquired in early life. Perceiving colour distinctions and colour similarities are basic to colour perception. If, for example, in a colour combination, the colours have the same whiteness, blackness, chromaticness, hue or lightness, we can sense that these colours have something in common. We often say that colours in such colour combinations fit together or harmonize or that the colours of a painting or a room hold together. This experienced unity of colours, however, has nothing to do with preferences. It follows from the visual system itself: the ability to recognize colour distinctions and colour similarities is part of the categorical perception and is therefore predetermined. It is natural in the same sense as recognition of characteristic colour scales in perceptive colour systems. Direct experience By direct experience we gradually learn through living to understand the relations of colour and light to the world around. The direct experience is dynamic and simultaneous; percep- 42

45 NORDIC LIGHT & COLOUR tions, feelings and emotions form a coherent whole. Making use of natural perceptual abilities (the categorical perception) and interplaying with the physical world we develop perceptual skills ; we acquire abilities to catch the spatial significance of colour and light in space. We also learn to recognize the perceptual qualities of materials, how they feel and how colour and light relate to them, etc. Patterns of sense-qualities always belong to functional situations in life, each one having a characteristic perceptual and emotional content; the light always illuminates something, it is always something that has a colour, and a spatial situation always has a special atmosphere. Direct experience provides spatial understanding, meanings, and emotional content to the physical world around. The German philosopher Gottlieb Baumgarten, originator of Aesthetics as a specific academic discipline, describes knowledge that implies a coherent intuitive understanding and is given to us directly by sense experiences. Baumgarten claims that aesthetic knowledge constitutes logically based knowledge, that sensible cognition is the ground of distinct cognition; if the whole understanding is to be improved, aesthetics must come to the aid of logic (Baumgarten 1983: 80). The tacit meaning of the direct visual experience of colour and light, materials, textures and objects is an aspect of our aesthetic approach to the world. Indirect experience In the outer circle we find indirect experience - principles, concepts or models that help to understand or give perspective to experienced phenomena in the two inner circles. Being embedded in cultural expressions (history, traditions, customs, trends, scientific theories, art, poetry, etc.), indirect experience forms a cultural context to which all experiences of necessity are related. History, scientific theories and theoretical models provide a basis of explanation and analyses. Traditions and customs serve as guiding rules. Art and design, literature and poetry summarize common experiences: art and design with expressive or significant form, literature and poetry with verbal language. Thus indirect experience can convey meanings and feelings to phenomena based on direct experiences and categorical perception. The indirect experiences can change and be reinterpreted, but can never totally be taken in or controlled by the individual. Indirect experiences are implicitly present in all perceptions. Abstract figures or words can be associated with symbolic meanings and scientific theories may refer to perceptual appearances. A colour combination, a specific light situation, a designed object or a spatial design may as content of an associative symbol be connected with special concepts or feelings. Associative symbols are basically social/cultural understandings. They are arbitrary and can be changed or replaced. The associative symbols may not be mistaken for the emotional content that has its origin in direct experience and the individual s perceptual interaction and interplay with the world around. Being dependent on their origin the principles, models or concepts of the outer circle have indirect or direct relations to phenomena in the two inner circles: visual symbols and concepts used in perceptual colour or light theory refer directly to phenomena in the two inner circles, whereas concepts and symbols describing the outer world in abstract terms have indirect relations to them; thus words, figures and concepts based on physical analyses with quantitative measurements and instrumental methods have an indirect relation to perceptual phenomena. The three experience levels are interdependent and implicitly present in all perceptions. A perceived distinction between a red colour and other colours is a basic categorical perception. The experience of the colour of a wall whether in light or shadow is a direct experience of the world around. The knowledge that red has a special position in a colour system, or that red surfaces absorb electromagnetic radiation in a special way, or that red houses may be of high social importance, is based on indirect experience. Art and design have a special and complex relation to direct and indirect experience. On the one hand artistic works can serve as models or examples for how we may attend to light and colour in our direct approach to the world. On the other hand they are also, as appearances, direct experiences. Experiencing colour and light in a living context always includes emotional and intuitive understanding; we experience spontaneously spatial relations and moods in a cultural context. This is how our overall perception normally works. In adopting an aesthetic attitude we consciously attend to this spontaneous process of understanding; perceiving aesthetic qualities in art and design or in the world around means that we open up for reflection on experiences us such. The American philosopher Susanne Langer s aesthetic philosophy is a part of the epistemological tradition from Baumgarten. Connecting to Wittgenstein she asks, how do we give symbolic form to the tacit dimension of our direct experience? She claims that the emotional content we can experience in a piece of art or a designed object is symbolic in a special way (Langer 1957: 60); perceptual patterns of colour, light and form, abstracted from their normal context in life, can be used as symbols for felt life in pieces of art and in designed objects. Susanne Langer calls them logical expressive or articulated symbols (Langer 1953: 31) Wittgenstein (1993:19) says that feelings follow experience of a piece of music, just as they follow courses in life; a piece 43

46 Figure 1. Experience levels ( Model by Ulf Klarén) 44

47 NORDIC LIGHT & COLOUR of music consists of a sequence of tones. It has a structural resemblance to courses in life a rhythm, pauses and breaks, pitches, etc. and thus they can be used as examples. The auditory structure in music is not a course of life, but felt life abstracted in a logical expressive symbol. The same is true for all sensory experiences. The expressive symbols are what we may call the artistic or aesthetic dimension in pictures, in utility goods, in architecture; they can make us feel something in something or see something as something. Susanne Langer (1957: 73) describes them as objectification of feelings. As logical expressive symbols, colour and light expressions in art and design can serve as examples of direct experiences that may promote new perceptual approaches the world. The logical expressive symbols occur in the borderland between direct and indirect experience. What we are used to calling expression in an articulated object or space is perceived as a direct experience, but without being separated from its symbol. Encountering articulated patterns in a piece of art or a designed product we experience recognition. Susanne Langer says that in one way, all good art is abstract, and in another way it is concrete (Langer 1957: 69). The aesthetic dimensions in art and design are, depending on aspect, both direct and indirect experiences. Conclusion In a sense colour and light are always something else. They have many aspects and their relations to different levels of experience must always be considered. Our visual experience is not without structure or laws and there are certainly many concepts describing it. One could even say that there are too many and disparate concepts to be useful in communication. What is emphasized here, however, is the need for a coherent and well defined overall structure of content. Without a comprehensive structure of content it is not possible to see how different kinds of colour and light experiences and colour and light concepts are related to each other, or in what respect they refer to different aspects of reality. 45

48 References: Arnkil, H., K. Fridell Anter & U. Klarén. (2012). Colour and light Concepts and confusion, Harald Arnkil, ed. Helsinki: Aalto University. Baumgarten, Gottlieb (1983) [1739]. Texte zur Grundlegung der Ästhetik. Hans Rudolf Schweizer, ed. Hamburg: Meiner. Billger, M. (1999). Colour in Enclosed Space. Göteborg: Chalmers University of Technology Fridell Anter, K. & U. Klarén (2009). Neutral Grey An Abstraction? In: Proceedings of the 11 th Congress of the International Colour Association (AIC 2009),CD. D. Smith, P. Green-Armytage, M. A. Pope & N. Harkness, Eds. Sydney: Colour Society of Australia. Gilchrist, A., C. Kyssofidis, F.Benato, T., Agostini, J. Cataliotti, X. Li, B. Spehar, V. Annan & E. Economou (1999). An Anchoring Theory of Lightness Perception. Psychological Review,Vol. 106, no. 4 : Green-Armytage, P.(2006). The value of knowledge for colour design. Color Research and Application 31(4): Gregory, R. L. (1966). Öga och Hjärna. (Eye and Brain). Stockholm: Aldus/Bonniers. Gärdenfors, P. (2000). Hur homo blev sapiens. Nora: Nya Doxa. Hering, E. (1920). Outlines of a Theory of the light sense. Cambridge: Harvard University Press. Klarén, U. & K. Fridell Anter (2011). Colour and light in space: Dynamic adaptation and spatial understanding. In: AIC 2011, Interaction of Colour & Light in the Arts and Sciences, Midterm Meeting of the International Colour Association, Zurich, Switzerland, 7 10 June 2011: Conference Proceedings, CD. V. M. Schindler & S. Cuber, Eds. Zürich: pro/colore: Klarén, U. (2012). Natural experiences and physical abstractions - On epistemology of colour and light. In: Colour and light - Concepts and confusions. Harald Arnkil, Ed. Helsinki: Aalto University School of Arts, Architecture and Design. Langer, S. K. (1957). Problems of Art: ten philosophical lectures. New York: The Scribner library. Langer, S. K Feeling and Form. London: Routledge & Keagan. Liljefors, A. (2006). Ljus och färg i seendets rum. In: Forskare och praktiker om FÄRG LJUS RUM. K. Fridell Anter, Ed.. Stockholm: Formas: Matusiak, B. (2006). The impact of window form on the size impression of the room. Fullscale studies. Architectural Science Review 49 (1). Merleau-Ponty M (2002) [1962]. The Phenomenology of Perception. London, New York: Routledge. Newton, I. (1952) [1704]. Opticks, Or A Treatise of the Reflections, Refractions, Inflections & Colours of Light. Facsimile with foreword by A. Einstein. London: Dover Publications. Noë, A. (2004). Action in Perception. Cambridge: The MIT Press. Prall, D. (1936). Aesthetic Analysis. New York: Thomas Y Crowell Co. Valberg, A. (2005).Light Vision Color. Chichester: John Wiley & Sons, Wittgenstein, L. (1992). Tractatus logico-philosophicus. Stockholm: Thales, Wittgenstein, L. (1993). Särskilda anmärkningar. (Vermischte Bemerkungen. G.H. von Wright/ H. Nyman, Eds. Stockholm: Thales 46

49 NORDIC LIGHT & COLOUR LIGHT AS EXPERIENTIAL MATERIAL Karin Søndergaard & Kjell Yngve Petersen ABSTRACT The article: Light as experiential material is concerned with the development of a psychophysical method of investigation, by which we can approach the experience and design of architectural lighting in research and education. To our eyes, light becomes visible in the meeting with substance, and in this meeting it reveals its characteristics, as it reveals the matter it meets. Even if light is perceived as visual account, and therefore belongs to the visual domain, our sensation and perception of light includes a larger complexity of embodied and cultural processes. Staged explorative situations offer concrete methods on psychophysical approaches for the investigation of architectural light design. The psychophysical method in discussion stages multi-sensory experience and inaugurate evidence on the basics of experiential accounts. The methods developed derive from performance and installation art and uses these art-forms as systematised frameworks and exercising methods to constitute an embodied and aesthetical approach in the work with architectural lighting. 47

50 Light as material spatial and form-giving characteristics It is commonly agreed, [l]ight is a prerequisite for our ability to see and experience the world around us. Light describes the surroundings on the basis of the variation of light intensities that reach our eyes. Light and shadow tell us about form, material, softness and hardness, lightness and weight (Mathiasen & Voltenen 2008:115). As argued by the Danish architect and light designer Merete Madsen, light is to be considered as a sort of architectural material, because in a very direct way [light] is a constituent part of the shaping of a space (Madsen 2004:34). The particular quality of daylight as material is, that it is of a changing and intangible character which is specifically qualifying exactly because of [this ambient] liveliness that is transmitted into a space (Madsen 2004:34). Following Madsen, regarding light as a changing and intangible kind of material, means that you need to work with light by skilful thought more than by crafts (Madsen 2004:34). She concludes this by citing James Turell; A lot of the learning to work with light, since it doesn t form by working with the hands as clay does, is this working with light through thought (Madsen 2004:34). This article introduces methods for engaging in the sensation of light and how it unfolds as experiential qualities. The method introduces qualities of experiential engagement as well as strategies for conceptual analyses. The architect Juhani Pallasmaa also brings forth the idea of thought as a working mode, but relates to a multi-sensory and embodied mode of thinking: It is similarly inconceivable that we could think of purely cerebral architecture that would not be a projection of human body and its movement through space. The art is also engaged with metaphysical and existential questions concerning man s being in the world. The making of architecture calls for clear thinking, but this is a specific embodied mode of thought that takes place through the senses and the body, and through the specific medium of architecture (Pallasmaa 2005:46). To perceive the presence qualities of light as a material in itself involves both the sensing of light, the thinking through a working mode, and the analysis of light in its spatial and form-giving characteristics. The concept of light-zones, and simultaneously zones of darkness, is an approach to perceive, consider and analyse light in space considering the spatial and form-giving characteristics. As concept, light-zone(s) are areas, fields or zones of light. It is a way of considering light in space as forms of bubbles or spheres of light, which as light-zones can be compressed, expanded, combined, exploded, etc., all according to the character of the meeting between the light-zone(s) and the space itself (inclusive of the space s content). Thus, the daylight in a space can be regarded as a composition of light-zones (Madsen 2005). Light-zones are inseparable from the spatial context where they appear. The shape of the aperture (daylight) or armature (artificial light), as well as the distribution of (artificial) light sources, generates the particular illuminating effects, which is further influenced by the characteristics of the illuminated surfaces. The suggested method of experiential engagement described in this article, introduces a thinking through experiencing, which takes place through a multi-sensory embodied mode of investigation. Architecture as an experiential encounter The interest in articulating experiential accounts from within an embodied and multi-sensory engagement is an approach, which has references back in early experiential philosophy, and theatre and design practice. The difficulty is how to explain and bring evidence from the experiential qualities, and how to encounter an analysis that at the same time correlate with both outside observations and shared accountability. In citing Henri Bergson The objects which surround my body reflect its possible action upon them (Bergson 1988:21), Pallasmaa argues, [i]t is this possibility of action that separates architecture from other forms of art. As a consequence of this implied action, a bodily reaction is an inseparable aspect of the experience of architecture. A meaningful architectural experience is not simply a series of retinal images. The elements of architecture are not visual units or gestalt; they are encounters, confrontations that interact with memory (Pallasmaa 2005:63). Already in the 1920s at Bauhaus theatre provided a place in which to experience space (Goldberg 2001:102). They argued for the research logic in the approach of staged methods and evidence formats, leading to the emergence of performance exercises as abstract investigations into spatial and experiential phenomenon. Production of space was being experienced here as a dynamic constellations of movement and tensions that went beyond the addition or subtraction of volumes [ ] structures, forms, colours, light and above all rhythm became key categories of a new and elemental strategy in the research and construction of space. Walter Gropius called it research of essentials for a different, liberated architecture (Blume 2008:45). The Bauhaus investigations introduced the mobile space, the individually conceived spatial experience that follows the experiencer, which informs the architectural relationship at any moment and in any activity. As formulated by Walter Gropius [t]he stage work is intimately related to the work of architecture as an orchestral unit: both receive and give to one another reciprocally. As a consequence of this line of thought, artists in both stage work and architecture had to seek the basic laws of the relationship between man and space, the essence of 48

51 NORDIC LIGHT & COLOUR objects and life-processes organised by the design of space (Blume 2008:45). Lászlo Moholy-Nagy discussed this man-space relationship as a systematic means of training human perception, [ ] for expanding and sensitising the senses (Blume 2008:51). As a consequence of the introduction of analysis through abstraction, he was committed to an all-encompassing access to the phenomenon of space by understanding movement as an experience of a super-spatial reality of pure energies [ ] He defined vision in motion [ ] as seeing, feeling and thinking in relationship and not as a series of isolated phenomena (Blume 2008:47). The approaches with formal abstraction and multisensory integration generated a succession of method-driven approaches, which opened for body-centred experiential accounts as a core part of analysis, discussion and creation across artistic disciplines. Artforms as methods Architecture initiates, directs and organises behaviour and movement. [ ] A building is not an end in itself; it frames, articulates, structures [and] facilitates. Consequently, basic architectural experiences have a verb form rather than being nouns. Authentic architectural experiences consist then, for instance, of approaching or confronting building, rather than the formal apprehension of a façade; of the act of entering and not simply the visual design of the door; of looking in or out through a window, rather than the window in itself as a material object; or of occupying the sphere of warmth, rather than the fireplace as an object of visual design. Architectural space is lived space rather than physical space, and lived space always transcends geometry and measurability (Pallasmaa 2005:63-64). Like Pallasmaa speaks of architectural experiences as having a verb-form, back in the 1960s the artist Allan Kaprow advocated for an artform more verb-like than noun-like. Like Kaprow and Pallasmaa, the authors of this paper take an interest in the evolution of the experience while it is experienced, while all experiential components dynamically progress over time. How can the experience while engaged in the experience be qualified, and how is possible to enable a position of observation within the activity of experiencing and its dynamic developments and complex integration of perceptive components? Allan Kaprow, Robert Morris, and Dan Graham were among the many protagonists in the 1960s that made the first move towards what we nowadays term as installation art. Installation art is considered as a hybrid discipline, which includes architecture and performance art in its parentage (Oliviera 1994:7). Through their engagement with the performing arts the artists became involved with the experiential aspect of performing in itself, and they began to develop strategies in order to arrange situations by which the audience could be disposed for a similar explorative experience. Whereas Morris works constitute examples of working with sculpture or objects as architectural gestures, Kaprow approaches the participatory engagement in itself, and work towards a calculation of organised improvisations as a step toward participatory involvement into the structure of works. He invented concepts such as the happening and the activity. Activities do not have audiences since the performer and experiencer is the same (Kirby 1969: ). An activity is an improvisational structure that collapses the traditional oppositional role between audience and actor, and makes the audience engage performatively into a kind of extra-daily behavioural situation. Our suggestion is to make use of artistic strategies such as Kaprow s activities and Morris architectural gestures to develop on a systematised framework of methods to constitute an experiential system of approaches in the work with architectural lighting. PSYCHOPHYSICAL ENGAGEMENT Light and sensory experiences When comprehending light as architectural material, by which we are enabled to shape spatial conditions, we realize how light can be considered as a primary in architectural thinking, and how it can develop as a primary concern of experiential thought. How the form characteristics of light actualize and is perceived as experienced phenomena, can be analysed as zones of light and darkness. To our eyes as a sensory experience, light becomes visible in the meeting with substance and in this meeting it reveals its characteristics as it reveals the matter it meets. But as an experiential account, the light experience becomes a complex integration of all the aspects of psychophysical engagement that a lived experience entails. We consider light to be perceived as vision and therefore belonging to visual domains. However, the concrete human experience of spatial light qualities is a multi-sensory experience and works with a polyphony of the senses, [by which] the eye collaborates with the body and the other senses, as Pallasmaa (2005:41) observes; a perceptive condition basic to human experience. As humans we access and relate to the world through our senses and actions, our senso-motoric capacities, and the construction of phenomena in the environment, such as architectures and light formations, are negotiated in the relation between the body and the environment. 49

52 FIG 01. Rehearsing multi modal sensibilities. Students in daylight studio explore the perceptual mode of engagement discussed as an extra daily state. The spatial conditions are explored through action/activities to enable an explorative position from within an experiential account. 50 FIG 02. Rehearsing multi modal sensibilities. Students in daylight studio engaged in a multi sensory exploration of spatial conditions generating a meta-conception of the perceiving self.

53 NORDIC LIGHT & COLOUR Following Pallasmaa Sensory experiences become integrated through the body, or rather, in the very constitution of the body and the human mode of being. [ ] Our bodies and movements are in constant interaction with the environment; the world and the self inform and redefine each other constantly. [ ] [T]here is no body separate from its domicile in space, and there is no space unrelated to [ ] the perceiving self (Pallasmaa 2005:40). Every touching experience of architecture is multi-sensory; qualities of space, matter and scale are measured equally by the eye, ear, nose, skin, tongue, skeleton and muscle. [ ] Instead of mere vision, or five classical senses, architecture involves several realms of sensory experience which interact and fuse into each other (Pallasmaa 2005:41). Performative engagement as a psychophysical method The psychophysical method discussed below is a method by which we can approach experiential explorations of light in its complex modes of appearance and inaugurate evidence on the basics of experiential accounts. The notion of psychophysical and performative engagement derives from the field of theatre and actor training techniques and as such include movement and action as structural tools for improvisational systems by which the beholder are enabled to investigate how he/she engages with a given surrounding - space, room or place. It is a perceptive method that activates the whole human bodymind, an approach by which we investigate how we experience being in a given space, and what psychophysical impulses different orchestrations of daylight or different composed artificial light settings accumulate. In exercising this training you are occupied with techniques that structure both body and mind generating a heightened state of engagement towards the surrounding space and what is at stake in that space. These techniques are of course designed as methods to help the actor perform on stage. But for the practitioner these techniques produce or build up an experiential capacity as a certain intuition on spatial concerns. Within theatre anthropology this shared and common phenomenon is discussed as an extra-daily state. Extra daily & pre-expressive In the course of the training the performer develops a capacity for performing, a scenic behaviour which is distinctly different from her every day behaviour. The performer s practice is, according to the theatre director Eugenio Barba, the behaviour of the human being when it uses its physical and mental presence in an organised performance situation and according to principles which are different from those used in daily life (Barba 1995:vii). The actor and director Phillip Zarilli speaks of an inner awareness [ ] toward a heightened [ ] state of engagement (Zarilli 2007:57). This heightened state developed within performance practice, Barba terms an extra-daily mode of presence, distinct from daily life behaviour, - obtained through performing practices, and evolving as a consequence of a cultivated technique. The reference to an ordinary behaviour and daily use of techniques such as eating, walking, and sleeping is based on the anthropologist Marcel Mauss (1950) concept of daily activities. These ordinary behaviours are understood as human techniques conditioned by culture and everyday situations, embodied in human action and structures of social disposition. The concept of extra-daily is then the utilisation of specific body techniques which are separate from those used in daily life (Barba 2007:257). The extra-daily expressive capacity of the expert performer is what Barba terms pre-expressive, a way of working particular to the performer. According to Zarilli the pre-expressive capacities are characteristics shared by systems of training/ exercise through which the actor works on oneself. [ ] [E] exercises are not simply a means of toning the physical body, but creating an entire new awareness of the actor s internal life not in a psychological or behavioural sense, but as a psychophysiological means of encountering the performative moment [ ] a bodymind awakened, sensitized, made newly aware or fully concentrated (Zarilli 2002:89). Concepts such as the extra daily mode and pre-expressivity enable a discussion on the acting techniques as tool and method in itself that can be utilised in disciplines such as architecture and lighting design, to explore and enhance the potential qualities of engagement with a given spatial environment. Exercising pre-expressivity The extra-daily capacity of pre-expressivity is developed and refined in exercises. The exercises situate the performer in a working relation to him/herself, organised within formal structures, which enables a focus on the art of the performer as an independent field of practice. The exercises are formal training devises, and the exercise forms are empty [ ] they are filled with [ ] concentration (Barba 1995:101), enabling 51

54 FIG 03. Rehearsing multi modal sensibilities. The photo catches a moment in a one hour long progressive improvisation exercise organised by rules/scored activities. The improvisation constitutes an exercise machine, which synthesize an explorative practice providing sensory thoughts. FIG 04. Embodied Thought. Experiential engagement in daylight studio exploring a light-zone from skylight opening, and experiential engagement in artificial composed light-zones in a black box theatre. 52

55 NORDIC LIGHT & COLOUR a focused situation for the development of pre-expressive capacities. Barba (1995:100) suggests the exercise event to produce a paradigm of dramaturgy, that is, a situation where a specific mode of presence is enhanced by way of the exercise. This extra-daily presence develops through an emergence of a second nervous system, [or a] memory, which acts through the entire body (1995:100). The exercise is a versatile environment for investigation and development of a variety of extra-daily behaviours, as Barba (1995:100) explains: In each case it is a question of a well-contrived web of actions. [ ] Exercises are pure form, dynamic developments without a plot, a story. Exercises are small labyrinths that the actors body-minds can trace and retrace in order to incorporate a paradoxical way of thinking, thereby distancing themselves from their own daily behaviour and entering the domain of the stage s extra-daily behaviour. The improvisation exercises are driven by tasks, as scored activities, which develop into exercise machines. Figure 3 shows students engaging in an improvisation guided by such instructions, and, in a paradoxical way of thinking as an embodied mode of thought, experience themselves acting and sensing, reflecting on their own experiential situation. These senses not only mediate information for the judgement of the intellect; they are also a means of igniting the imagination and of articulating sensory thoughts. Each form of art elaborates metaphysical and existential thought through its characteristic medium and sensory engagement (Pallasmaa 2005:45). The task utilized in the exercises, driving the development of experiential capacities towards light phenomena, are particular to the architectural context, but fundamentally awakening very similar spatial sensibilities as those of the performer. The strategic method can be slightly adjusted to the particular task, adapting to the medium and qualities under investigation; for instance the phenomena of light-zones. The strategic method to some extent evolves a new sensecapacity, a new ability of critical relation to light phenomena, which to some extent will remain and develop as a personal capacity. This is an extra-daily capacity that can be mobilised through these methods, these systems of activities, engagement and staging strategies. There is potentially opened for a field of experiential practice of thinking through performative engagement, which could be transferred to other enquiries by adapting the particular approaches to the phenomena of interest. EXPERIENTIAL ENGAGEMENT Spatialization and temporalization The change from observing from the outside, towards experiential observations from within generating the experience, is an investigatory style that actively challenges the conceptions of space and time. There is opened for an analysis where everything is in constant change, where the basic phenomenal status of space and time is altered towards modes of spatialization and temporalization. That means that the sense of space unfolds as notions of place and direction, nearness and distance. Likewise the sense of time is formed by the duration and hesitation in the actions. In everyday life, space is normally understood as a stable context wherein temporal events occur. Pallasmaa suggest, Architecture is our primary instrument in relating us with space and time, and giving these dimensions a human measure. It domesticates limitless space and endless time to be tolerated, inhabited and understood by humankind. As consequence of this interdependence of space and time, the dialectics of external and internal space, physical and spiritual, material and mental, unconscious and conscious priorities concerning the senses as well as their relative roles and interactions, have an essential impact on the nature of the arts and architecture (Pallasmaa 2005:17). A consequence of the method with performative engagement is that the notion of space as stable is substituted for an experiential account, where spatialization is a consequence of the human activities; the walking, the direction of attention, or the hesitation when considering the possible future actions and movements to be performed. The sense of space is a construct generated by the way we think space. In the method of performative engagement the experience of space unfolds and actualises; space in itself [ ] is not static, fixed [ ] though perhaps we must think it in these terms in order to continue our everyday lives. [ ] Space, like time, is emergence and eruption, oriented not to the ordered, the controlled, the static, but to the event, to movement or action (Grosz 2001:116). The perception of spatialization and temporalization is an experience of continuous unfolding, an emergence in the present, of the virtual becoming actual. As Grosz explains it: [o]ur perception is a measure of our virtual action upon things. The present, as that which is oriented towards both perception and action, is the threshold of their interaction and thus the site of duration. The present consists in the consciousness I have of my body (Grosz 2001:121). Consequently the modality of presence becomes an ever transforming extended now, a mode of duration, where the [d]uration [ ] is a mode of hesitation, [ ], unfol- 53

56 FIG 05. Simple composition/design of a square & sharp, and, a round & diffuse light-zone. The two different designs serve as models for exploration. 54 FIG 06. Light design in the black-box of a square & sharp, and,a round & diffuse lightzone. This image gives a sense of the presence and volume of the light-zones.

57 NORDIC LIGHT & COLOUR ding, or emergence (Grosz 2001:114). In the extreme version of exploratory engagement, we could say that the virtual time and virtual space become mutually generative, where intensities of both spatialization and temporalization is mutually generated and modified within the investigatory activity. A further perspective could be to develop models for virtual time becoming virtual space (Grosz 2001:120), enabling analysis of futurities and other alternate actualities. The systematic experiential engagement generates a self-reflective presence, which enables a testing ground for thoughts across time and space parameters. That is a staged explorative design condition where the complex relations between the designed and the experienced can be interrogated. The question is how the world is experienced while in action, and how these insights might inform transient perspectives and enable thinking of the experiential in architectural invention and experimentation. If we image an involvement in spatial investigations where the detailed fixation and measurement is not the primary aim, but rather the multimodal engagement and the senso-motoric orientation, then we engage with the flesh of the world as Pallasmaa argues: The very essence of the lived experience is moulded by hapticity and peripheral unfocused vision. Focused vision confronts us with the world whereas peripheral vision envelops us in the flesh of the world (Pallasmaa 2005:10). Experiential accounts from within light-zones The staged investigations use a simplified light formation and spatial context: a simple design of light-zones with theatre luminaires and staged in a black-box environment, where the spatial qualities and directions are formed by the light setting only. The particular context for these investigations of experiencing light through theatrically designed light-zones also opens for an investigation of light formations as a material in itself. The spatial and form-giving characteristics of light-zones and darkness-zones can be described as follows: Light-zones create areas, places or zones to be in, whereas zones of darkness create thresholds and transition zones. The composition of light-zones and darkness-zones also change the appearance of a space. Perceptually, bright surfaces seem to advance and expand in space, while darker areas seem to diminish and shrink. Furthermore, the daylight of a light-zone has the potential of revealing space, form, and matter, whereas deep shadows and darkness conceal (Madsen 2005). In the investigation discussed here, a square light-zone and a round light-zone are models for exploration. The two light-zones constitute a set of basic and very simple designs, where it is possible to comprehend the design decision before entering into experiential investigations. The light-shapes are constructed by theatre luminaires in a black-box environment. It is a simplified version of two types of light-zones: one round with diffuse edges and one square with sharp edges. The construction of the light-zones is explicit, one can see the luminaires and the lit form on the floor, and the volumes of the light-zones are very easily understood by holding out a testing hand. As such, a district volumetric light design is present while simultaneously enabling an experiential investigation of other non-volumetric qualities of the light-zones. The two staged light-zone designs constitute a rehearsal environment for the development of pre-expressive capacities towards these particular light formations. Below is a summary of observations (Søndergaard 2010: ), collated from several investigatory events, which gives a view into the sensibilities evoked by the exercise. The sharp and square light-zone evokes the sensation of a defined place, with rigid directional features, and is experienced as clearly separated from the larger surrounding space. Standing in the darkness outside of the sharp/square light-zone is sensed as inhabiting a definite other space. Any position of standing or way of moving, inside or outside, is sensed as always defined by the shape of the light-zone rather than defined by the persons positions or movements. The sharp/square light-zone establishes a distinct place to visit or inhabit, and promotes tendencies to maintain clear positions and stay still. The sharp/square lightzone makes people intensively aware of each other, often resulting in defensive body postures, or leading to constant re-negotiation of positions and relative directions. The situation causes a build-up of suspense among people, and actions such as touching or looking at each other triggers immediate reactions. There is an increased experience that people individualize themselves from the group, and encounter each other in restless demands of the relations to one another, in continuous detailed negotiations of the social operations of the group. The diffuse and round light-zone evokes the sensation of a gradual intensity of a location, and can be identified and related to as a particular zone even when standing out in the darkness. There is no sense of direction and no particular separation of being inside or outside the light-zone. This lack of distinct separation evokes a sense of one unified place, equally qualified by the all grades of lightness/darkness as part of the same placeness. The diffuse/ round light-zone produces a varied sense of place and directions depending on where one stands and how one move. People s positions and movements, more than the shape of the light-zone, defines the placeness qualities, and this sensation is further intensified through exploration. In the diffuse/round light-zone, people 55

58 FIG 07. Embodied Thoughts. Methods of performative engagement for explorative exercises of simple light-zones. FIG 08. Triangular experiential negotiation. The photo shows a situation from a white box environment, where a group of six students are rehearsing the triangular system, involved in an experiential negotiation rotating in-between three different observation positions. 56

59 NORDIC LIGHT & COLOUR can move around getting really close seemingly without tension. People behave relaxed, informal and they do not seem to uphold any positions or to challenge each other. Simultaneously as they are touching and even hanging on to each other, they are not producing distinct positional roles or separate individual agendas in relation to each other. On the contrary there is even a tendency that each person could seem to create her own individual sense of realm but still interact with the group. Triangular experiential negotiation The complex of perspectives and self-reflective positions, which is part of the pre-expressive capacity and extra-daily state of engagement, can be organised in a simple triangular methodological system by a team of investigators. The cooperative approach enables the development of a shared language on the experiential accounts, the development of shared analytic capacities, and facilitates an experimental environment for the exploration of emerging possibilities and qualities. The triangular method operates with a selection of observer roles similar to the self-reflective position of the performer, and is specific in the way it situates a collective of investigators in different positions of observation within the same explorative engagement. The method enables a structure of engagement by which a group can share a firsthand experience and explore this same experience from different positions as a comparative qualitative investigation. The triangular set of observer positions: 1. The first participant observes from a position inside the experience of a performative engagement, wherefrom the light zone is explored and the participant speaks from her firstperson experience. 2. The second participant observes from a position outside the light zone in continuous discussion with the first, a referent position as external observer who interviews, reflects on and registers the first-person experience. 3. The third participant observes from an outside position and uses a camera to frame and document the first-person experience likewise from an external position. Each of the roles is a distinct experiential position, which creates a set of mutually critical position for observing the exploration from within the experiential process while performing the engagement. Together, the three positions maintain each other in a triangularity of performative engagement in an organised performance situation and generate a shared mode of presence similar to that of the performer s extra-daily state. The team repeatedly change positions to make sure that each person rotates through all positional roles several times. The participants synthesise their experience of all three observer positions, and attain a capacity for overviewing the totality of the situation and the relational operations that qualifies it. The solo experience from any of the roles by themselves will lack the mutual constitution process, whereby they integrate the three modes of engagement. The reflective coordination between the three positions in the moment, as a shared experiential event, is a crucial quality of the method. After a process of adapting the method, understanding how is works as a processual tool, the participants can stage similar explorative/ analytic/generative processes on any other topic that need an experiential design approach. The experiential accounts, and the pre-expressive capacity, is in this way no longer a unique personal phenomenon, but brought into a collective discussion and formalised as shared observations. The triangular performance analysis also enables the individual to gain an overview from both within the experience, from outside, and in negotiation. This organised situation forms an extra-daily mode of analytic presence, which is developed as a capacity for future investigations and design processes. (Petersen & Søndergaard 2011:90) EXPERIENTIAL ARCHITECTURES Architecture as staging devise The idea of architecture as having a staging agenda embedded for people to improvise their daily life was eagerly discussed by the architect Steen Eiler Rasmussen already in the 1950s. In his thinking, the architect acts as a theatrical producer, [ ] who plans the setting for our lives (Rasmussen 1959:10), and he suggested human experience as a primary source for architectural design strategies. The architectural theorist Marianne Krog Jensen takes Rasmussen s argument even further in stating, architecture is a cultural action [ ]. We no longer ask what architecture is; we ask what it does. Space is something that unfolds; it is defined through movement, action and creation (Jensen 2010:81). The experience of architecture emerges out of the activities of living and is shaped by the negotiation between our experiential accounts and our performative engagement. 57

60 FIG 9. Exercise Machine in a laboratory setting. The Frame as an architectural gesture; embedded staging agendas by way of composed zones of light. 58 FIG 10. The Frame and light-zones as Exercise Machine staging experiential situations, where the light setting operates as an embedded dynamic structure, promoting an enhanced sense of spatial negotiation.

61 NORDIC LIGHT & COLOUR Thinking of architecture as an artistic composition of physical appearance that shapes the conditions for our living, we need to include an understanding [of] man and his surroundings as flows that constantly interact and transform each other (Jensen 2010:84). In this understanding architecture deals with experiential processes and situations in which also social spheres are at play, and space appears as an emerging phenomenon that is constituted in the instantaneous experience of it. The suggestion is to arrange staging devises as rehearsal machines for extra daily and pre-expressive capacities. Thinking of architecture as a staging devise that maintains a particular time and space form, a firmness in the world to relate to, a context for presence and directions, opens for an method of staging experiences using architectural elements, which frames, halts, strengthens and focuses our thoughts, and prevents them from getting lost (Pallasmaa 2005:45). To situate experience as a critical medium in architectural processes means working with the production of experiential forms of material evidence, which could be pursued through the staging of specific experiential situations. Staging improvisation in exercise machines As discussed, the training of pre-expressivity in staged situations develops a certain heightened self-reflectivity, a technique of acculturation [that] artificializes [ ] the performer s behaviour (Barba 2007:257) and builds an ability to observe action and observe observation while in action, an extra-daily mode of attention and action. The stagings work as exercise machines that put the [participant] to the test through a series of obstacles [and] allows the [participant] to know [ ] herself through an encounter (Barba 1995:101), where the staging devise situates a specific focus on an aspect of herself as a performing entity, and in this way situates an analytic site for advanced self-reflection on pre-expressive capacities as a distinct extra-daily behaviour. The pre-expressive preparedness facilitates a qualified situation for improvisation in a staged event, an elaborate mode of extra-daily behaviour that skilfully allows the participant to articulate through formal pre-expressive activities. This architectural staging effects the situation as a habitat for the architect to improvise extra-daily behaviour. The staging can be considered as an exercise machine that makes improvisation possible by its contextualising framework, as an open possibility for engagement, and at the same time directs a particular condition for the improvisation activities, specifying how to engage. The frame-object combined with light-zones The staged investigations use a simplified spatial object: a frame object the size of a wall. Placed in the theatrical blackbox environment, the light formation is a simple design of lightzones with theatre luminaires on each side of the frame-object. The frame is a simple architectural object, which divides the space in two identical mirrored areas, and is designed to stage an external exercise machine. The frame-object is even sized horizontally and vertically, 230x230 cm, with a boarder size of 35x35 cm. The hole in the frame-object situates the viewing of humans in full size on the other side. Two identical light-zones, one on each side of the frame-object, produce an even placeness characteristic on both sides of the frame-object. The frame-object introduces a distinction that separates space in two sides and arranges for human relations to be explored. According to Grosz, the staging of a wall generates this distinction, and constitutes the possibility of an inside and an outside, dividing the inhabitable from the natural. [ ] The wall divides us from the world, on one side, and creates another world, a constructed and framed world, on its other side (Grosz 2008:14). The staging of the frame and light-zones enable investigation into how the spatial configuration instantiate high-order relationships among people, and how the light setting promotes performative engagement. The distinction generated by the frame-object marks certain relational possibilities, and provides new connections, new relations, social and interpersonal relations, with those on its other side (Grosz 2008:14). The frame-object allows people to be confronted, and enables a symmetrical relationship between the sides of the frame-object. The frame-object can be passed and is therefore simultaneously abstract and concrete, a separator and a passage, and it stages a social agreement on a certain set of social framing operations. Dynamism originating from the light design The design of the light-zones indicates enclosed areas, with diffusion on the border between light-zone and dark-zone, and with the priority of a higher lit area central to the framed perspective. These priorities of light are further arranged in a way that produces a varied pattern in the light, not dissimilar to an everyday daylight experience. The dynamic transformational aspect of daylight consequently evokes a varied spatial experience. In the frame-object the variations in the artificial light design is used as a way to promote performative investigations. The light design is stable over time but varied over space, and every movement by the investigator is enhanced and qualified by the experience of light variation, 59

62 FIG 11. Daylight workshop. White-cubes used as sites for the construction of kinetic systems, which orchestrate dynamic compositions of light-zones in the cubes. FIG 12. Daylight workshop. The students build kinetic daylight instruments in the white cubes, which channel and shape daylight. 60

63 NORDIC LIGHT & COLOUR while standing still leaves the investigator with no feedback. The light intensity, and how light falls onto the bodies, changes depending on how and where they move. This differentiated intensity makes people move in the examination of how the light is experienced at different places in the lit areas. These are qualities that operate as an embedded dynamic structure, and lead the investigators into a dynamic state of investigation. Staging nearness and distance The frame-object causes a particular experience of being coupled with the other on the opposite site. The frame that separates somehow legitimates this intimate sense of coupling. The felt or imagined distance caused by the complexity of the situation can t be measured in measurable parameters but is comparable to standing in front of a mirror, just with the notable difference, that it is not yourself you see on the other side of the framing, but another person. The two equal behavioural conditions, placed opposite each other, generate an enhanced sense of nearness while simultaneously producing a sense of enhanced distance. Grosz speculates on the qualities of spatialization: If past, present, and future are always entwined and make each other possible only through their divergences and bifurcations, then perhaps there is a way to consider spatiality in terms of relations of nearness and farness, relations of proximity and entwinement, the interimplications of the very near and the very far, rather than of numerals or geometry (Grosz 2001:129). The frame-object is deliberately designed to promote a particular experiential condition, an enhanced sense of spatial negotiation. The two ladies standing close on each side of the frame-object (figure 10) are in a deep investigation of the nearness qualities evoked by the staging. Grosz speculates along the lines of how architectural devises can be said to promote certain experiential conditions. In this case the frame-object stages a continuous re-emergence of virtual-actual relations, within which the ladies are engrossed. This possibility returns us once again to the vexing question of the virtual and its particular spatial resonances. One cannot of course directly specify what a virtual is, for insofar as it is, insofar as it exists, it exists as actual. In the process of actualization, the virtual annuls itself as such in order to re-emerge as an actual that thereby produces its own virtualities. At best one can specify what the virtual may produce, what effects or differences it may generate (Grosz 2001:129). WHITE-CUBE INVESTIGATIONS ON EXPERIENTIAL LIGHT DESIGN Explorative processes of experiential light design The performative method has been successfully used as a tool in daylight workshops at the School of Architecture, Copenhagen, generating a specific mode of investigative practice with explorative thinking through various procedures of abstraction. The specific focus in the courses is on daylight kinetics, that is, how kinetic structures form the daylight influx. The students investigate possible designs of daylight openings, and interrogate how these designs are imperative for the unfolding of the spatial qualities of lightness and darkness. The development of prototypes and experiential evidence emerge through a series of authoring processes, iteratively refined and often overlapping or re-visited: 1. The students develop particular experiential sensibilities through performance training 2. Ideas are tested through serial explorations of design possibiliies in model sketching 3. A select model is built as a full-scale prototype 4. The team of students engage in repeated experience of light situations within the prototypes The full-scale prototypes are white cubes, 240 cm on all sides, with an open top fully exposed to the sun and the sky. The investigation explores the effect of the highly complex and dynamic daylight inflow, introduced as experiential staging of architectural lighting designs. The projects described investigate kinetic daylight mediators and their effect on the light qualities and colours of the interior surface and volume of the cubes. The daylight explorations make use of the experiential techniques to stage situations in which the students simultaneously act, experience and directs their own processes of performative engagement. This method operates, as described previously, with a selection of observer roles, and is specific in the way it situates a collective of investigators in different positions of observation within the same explorative engagement. The first participant observes from a position inside the experience. The second participant observes from a position outside the light zone in continuous discussion with the first participant. The third participant observes from an outside position and uses a camera to frame and document the first-person experience. Figure 13 shows the external observers standing on ladders, taking notes and shooting photographs, while the experiential participant explores the light situation in the white-box. 61

64 FIG 13. Daylight workshop. Students use the triangular system of exploration at the white cube site. While one person is engaged in performative explorations within the cube, his fellow colleges are observing from the outside standing on ladders. FIG 14. Daylight workshop Composing light-zones in white cubes by way of kinetic instruments. 62

65 NORDIC LIGHT & COLOUR The students develop extra-daily orders of reflection, explore possible design strategies through models, build prototypes, and explore the light situations they have instantiated. In the preparation of the prototype environments, the students iteratively stage experiential investigations to guide the design process, moment by moment observing and reflecting on these processes of engagement while these unfold, and altering the design accordingly. Virtual as potential Following the architectural philospher Elisabeth Grosz the sense of being situated as participant could be said to be a staging of a certain virtuality, a potential (Grosz 2001:93). The potentials can be identified as those virtual possibilities that specify the contexts for the actualisation of the experience at any moment. The actualisation of the virtual is a way to understand the dynamics of that which the experience potentially is to become. The awareness of the engagement and the context of the situation are generated simultaneously as the event progresses. The suggestion is to compose virtual potentials, which prepare for particular experiences to emerge from the processes of engagement in the staged event. In line with S.E. Rasmussen, the architect is a theatrical producer, understanding theatricality as our virtual projections upon experienced situations (Feral 2002), that is, how we through our activities, senses, and memories develop imaginary potentials of the given situation and hereby shapes futurity, shapes potential focuses on the matter investigated, shapes visions to be practically investigated. The participatory experience in staged situations is, according to Dan Graham, especially evoking attention to a pure present tense and stages a heightened awareness towards how experience appears. He suggests, the perceptual process should [ ] be understood as a continuum spanning past, present and future (Graham in: Bishop 2005:72). The philosopher Henri Bergson (1988) discusses this notion of the present as an expanded durational experience and as an extended site of perceptual negotiation. He argues for a lived reality located in the processes between appearance and memory, as a matter of memory that operates on the relation between what exists and what appears, that is, the relation between our activities in the present and our perception of our presence. Elizabeth Grosz suggests this realm of perceptual negotiation as a process of the actual entering into negotiation with the virtual, arguing duration as an actualisation of the virtual as that element of the past which contains the potential to generate a future different from the present (Grosz 2001:xx-xxi). When rehearsing the ability to exercise experiential engagements, the methods used and qualities attained becomes a multisensory and embodied mode of thinking; and expert practice of what Pallasmaa (2005:46) points at as embodied thought, brought to a level of skilled capacity that enables an experiential position in architectural design processes. What is the qualities in wandering, hesitating, moving in the flesh of the world? Is it also, through embodied thought and being embedded in the world, to start imagining new possibilities; to imagine experiences of light and pursue the virtual as potential, expanding on the experienced qualities using the triangular method, and designing from the dynamic experiential position; from within experiencing? Experiential engagement with architecture The prototype development has the ability to stage experiential situations. The prototypes are designed as formal architectural experiential machines, which by way of the build-in staging capacities situate the participant in well-defined experiential situation. The experiential staging transfers their insights body to body, a bodily identification as Pallasmaa suggests: We behold, touch, listen and measure the world with our entire bodily existence, and the experiential world becomes organised and articulated around the centre of the body. [ ] We are in constant dialogue and interaction with the environment, to the degree that it is impossible to detach the image of the Self from its spatial and situational existence (Pallasmaa 2005:64). In that way it becomes possible to articulate experiential account from one body to another, conveying qualities that are only accessible through direct experience. A kind of mimesis of the body with transfer of embodied insights through staged situations, similar to what Pallasmaa suggests is a core part of the architectural process: during the design process, the architect gradually internalises the landscape, the entire context, and the functional requirements as well as his/her conceived building: movement, balance and scale are felt unconsciously through the body as tensions in the muscular system and in the positions of the skeleton and inner organs. As the work interacts with the body of the observer, the experience mirrors the bodily sensations of the maker. Consequently, architecture is communication from the body of the architect directly to the body of the person who encounters the work, perhaps centuries later (Pallasmaa 2005:66-67). Staged explorative situations offer concrete methods on psychophysical approaches for the investigation of architectural light design. The psychophysical method in discussion stages multi-sensory experience and inaugurate evidence on the basics of experiential accounts. The methods developed derive from performance and installation art and uses these 63

66 FIG 15. Daylight workshop Composing light-zones in white cubes by way of kinetic instruments. FIG 16. Daylight workshop Composing light-zones in white cubes by way of kinetic instruments. 64

67 NORDIC LIGHT & COLOUR art-forms as systematised frameworks and exercising methods to constitute an embodied and aesthetical approach in the work with architectural lighting. The developed methods and the exercise-machines (or sites) allow for and legitimize personal experiences to be refined as aesthetical discussions in shared sites. The complexity of experiential awareness is structured as sites to be shared in the design investigations. In these experiential and explorative sites, terms such as futurity and virtual potentialities become accessible as shared conceptions in the design environment. Images Photographs by the authors Karin Søndergaard & Kjell Yngve Petersen, participants in the workshops, and Ole Kristensen, Simon Moe, and Karina Mose. Event partners The laboratory investigations on the square and round light shapes and the Frame object was organized in collaboration with Boxiganga Performance Theatre, Copenhagen ( ), assisted by Ole Kristensen and Simon Moe. Masterclass was organized in collaboration with Royal Academy of Fine Arts, School of Architecture, Architectural Lighting Laboratory, Copenhagen (2006), assisted by Architect MAA, Nanet Mathiasen. The White Cube workshops was organized and conducted in collaboration with Associate Professor, Architect MAA, Karina Mose (2011 & 2012), The Royal Academy of Fine Arts, Schools of Architecture, Copenhagen. 65

68 REFERENCES Barba, Eugenio (1995) An amulet made of memory. In Zarilli, Phillip B. (ed.) Acting Re-Considered. London: Routledge. Barba, Eugenio & Savarese Nicola (1995) The secret art of the performer. London: Routledge Barba, Eugenio & Savarese Nicola (2007) Pre-expressivity, pp , in Keefe, John & Murray, Simon (eds.) (2007) Physical Theatres: A Critical Reader. London: Routledge. Bergson, Henri (1988) Matter and Memory. New York: Zone Books Bishop, Claire (2005) Installation Art. London: Tate Publishing. Blume, Torsten (2008) Die historischer Bauhausbühne. In Bauhaus. Bühne. Dessau. Szenenwechsel. Blume, Torsten & Duhm, Burghard Eds. Berlin: Jovis Verlag GmbH Feral, Josette (2002) Theatricality: The Specificity of Theatrical Language, pp in Substance, Issue 98/99, Vol.31, nos.2&3, 2002, Madison: University of Wisconsin Press. Goldberg, Rose Lee (2001) Performance Art. London: Thames & Hudson Grosz, Elisabeth (2001) Architecture from the Outside. Cambridge: MIT Press. Grosz, Elisabeth (2008) Chaos, Territory, Art: Deleuze and the Framing of the Earth. New York: Columbia University Press. Jensen, Marianne Krog (2010) Space Unfolded Space as Movement, Action and Creation in Herforth, Kim & Martinussen, Kent (eds) How architecture shapes behaviour mind your behaviour. Copenhagen: DAC & 3xN. Kirby, Michael (1987) A formalist theatre. Philadelphia: University of Pensylvania Press. Madsen, Merete (2004) Lysrum [Light Zones]: as concept and tool. PhD dissertation. School of Architecture, Royal Academy of Fine Arts, Copenhagen. Madsen, Merete (2005) Light-zone(s): as Concept and Tool. An architectural approach to the assessment of spatial an form-giving characteristics of daylight. -cept-and-tool.php Mathiasen, Nanet & Voltelen, Nina (2008) Light and Shadow in Dahl, Torben (ed) (2008) Climate and Architecture. London: Routledge. Mauss, Marcel (1950) Body Techniques, pp , in Keefe, John & Murray, Simon (eds.) (2007) Physical Theatres, A Critical Reader. London: Routledge. Oliviera, Nicolas de & Oxley, Nicola & Petry, Michael (1994) Installation Art. London: Thames & Hudson Ldt. Petersen, Kjell Yngve & Søndergaard, Karin (2011) Material Evidence as Staged Experientiality, pp 80-91, in Beim, Anne & Ramsgaard Thomsen, Mette (eds) The Role of Material Evidence in Architectural Research. Copenhagen. The Royal Academy of Fine Arts. The Schools of Architecture, Design and Conservation. Pallasmaa, Juhani (2005) The Eyes of the Skin. Chichester: John Wiley & Sons LTD. Rasmussen, Steen Eiler (1959) Experiencing Architecture, Cambridge: MIT Press. Søndergaard, Karin (2010) Participation as media: a compositional system for staging participation with reflective scenography, pp extractions. Ph.D dissertation. CaiiA The Centre for Advanced Inquiry in the Integrative Arts, Planetary Collegium. University of Plymouth. Zarilli, Philip (2007) Senses and Silence in Actor Training and Performance. In The Senses in Performance Banes, Sally & Lepecki, Andrè (eds.) New York: Routledge. Zarilli, Phillip B. (2002) (re)considering the body and training. In Acting Re-Considered Zarilli, Phillip B. (ed.) London: Routledge. 66

69 NORDIC LIGHT & COLOUR EVIDENCE-BASED HEALTH CARE DESIGN - HOW CAN IT BE MEASURED? Aspects of colour and light Helle Wijk ABSTRACT The physical environment is increasingly recognized as important in health care but even though research on the interrelationship between residents in nursing homes and their physical environment has been concluded for, findings are seldom communicated with designers, architects and facility administrators. This essay takes a nursing perspective on environmental design with a basis in the notion that the physical environment represents an important part of nursing care. The characteristics following the disease should be the starting point when designing health care environments to minimize unwanted perceptions and feelings, and to maximize desired ones. By taking that approach, design could be regarded as a therapeutic resource to promote well-being and functionality among residents. 67

70 Introduction An increase of research studies focuses on the physical aspects of the environment as an important dimension of caring and quality of life, with the assumption that some of these aspects may be built into the way the health care environment is designed. For example it is well known that orientation in the environment can be facilitated by way-finding cues, symbols and proper lighting to enhance visibility (Ulrich, 2006) as well as that environmental factors both can act as support and hinder for adequate performance, interaction with family, fellow-residents and staff, increase health, feeling of security and safety. Adapting the environment to match the needs of the user can therefore be considered as a non-pharmacological treatment (Ulrich 2012). The healthcare environment should contribute to residents health and wellbeing and a person-centred care (Gesler, Bell, Curtis, Hubbard & Francis, 2004). Planning for new healthcare environments therefore claim a thorough analysis of the resident-related objectives that are expected to be fulfilled and the processes (care activities) and the space conditions that are considered necessary to achieve the objectives (Curtis, Gesler, Priebe & Francis, 2009; Vischer, 2008). By adopting this approach it is easy to see that the analysis must be a shared responsibility and be performed through collaborative planning with stakeholders from healthcare, architecture, design and building construction. According to Lawton (2001) there are five general categories of user needs: Decreasing unwanted behaviour, increasing social behaviour, increasing activity and increasing positive feelings and decreasing negative feelings. This is in line with studies demonstrating an increase of social activities among older residents as a result of an adapted environment that support function and interaction between the elderly residents (Liebowitz et al. 1979) as well as studies showing an increase in well-being by the implementation of a home-like design at dementia institutions (Küller 1991). Also an easy floor plan configuration and the use of concrete signs and symbols have shown to act as a supporting factor (Passini et al. 1998). Another environmental intervention important in old age is the avoidance of glare due to the often diminishing visual function following old age. Also the restriction of using pastel colours in relation to low colour contrast is highlighted since it is proposed that a more frequent use of contrasting colours can facilitate orientation and functioning in old age (Cannava 1998). As an example Passini et al. (2000) conducted a way-finding test for old people with severe cognitive decline where they could show that despite their cognitive condition they were able to find their way around. Critical features in the environment to support their orientation seemed to be the implementation of environmental information that was easy to interpret and identify and a great number of reference points. Also avoidance of floor patterns and dark lines that could increase anxiety showed to be important to support orientation. These studies are all examples of where the ability to interact and perform actions is used as cut off variables. That means that interaction and prevalence of adequate performance have been accounted for as measures of the success of an environmental intervention. An increased knowledge about the interaction between residents suffering from illness and their living environment are crucial for planning, designing and evaluating the quality of caring environments. Adapting the environment to residents needs A starting point in designing health care environments is to take interest in the preserved environmental perception instead of perceptual decline among the residents. This is in a way to reconsider caring from a focus on risk factors for pathology to a focus on health promoting issues. This approach, also named the salutogenic way of caring (Antonovsky 1987), advocates that the health of various degree, always present within the individual, should be the focus of caring instead of the disease. In other words, caring should put a stronger focus on what other strategies beside medical actions that could promote health for the resident. This interest on health and preserved functions instead of disease and lost functions is also in line with the concept of empowerment and person-centred care (Ekman et al 2011). By focusing on preserved function, and by implementing this knowledge in the environment and care of the residents, it is assumed that the persons opportunity to behave independently increase. Central concepts of nursing are the respect and dignity for the person as a whole in his environment with the overall goal to contribute to health and to support preserved functions. This is expressed in many nursing theories e.g. in Orem s (1995) model of nursing which focuses on strategies to compensate for the persons lack of self-care abilities. Central is that it is the knowledge of how the resident perceives the environment that is the starting point for environmental intervention (Wijk et al. 2002). The increase of research stressing the importance of environmental design to promote quality of life, is an important complement to the notion that competent cognitive functioning, the ability to perform everyday activities and engage in meaningful use of time has been found to be of immense importance in the population at large (Ulrich 2012). But even though that the knowledge base comprises of a variety of methods, still regrettably few can serve as hard fact design directives. 68

71 NORDIC LIGHT & COLOUR There are many factors influencing how we perceive and are able to function in the environment. Aspects such as type of walking surface, illumination and ambient conditions must interact with aspects which involve visual and auditory perception, balance, orientation and cognition in order to support safety. In summary there is a need for profound knowledge and understanding of the complex balance between environmental pressure and personal abilities. The ecological model of ageing as a framework for adapting the environment Characteristic features of the ecological model of ageing, developed by Lawton and Nahemow (1973), are that it predicts behavioural outcomes by looking at an individual s competence in relation to environmental pressure. The model is built on the following equation: B = f (P, E), where B stands for behaviour, f for function, P for person or competence and E for environment, i.e. behaviour is a function of the person and the environment. Competence is only a part of the person (P) and includes a person s biological health, sensory perceptual capacity, motor skills, cognitive capacity and ego strength. Adaptation is predicted by examining the match between competence and the demands of the environment. Environmental (E) pressure encompasses the multiple demands of the environment upon the individual. It includes aspects of the physical environment (lighting, orientation cues, geographic distance), the personal environment (family members, friends etc), supra-personal environment (characteristics of the residents in a person s neighbourhood), and the social environment (norms, values in the individuals society). According to the model the environments are classified on the basis of the demand character of the context in which the person acts. The demand character could be positive, neutral or negative. When the capacity of the individual is in balance with the pressure of the environment the demand character is neutral. If the individual competence deteriorates, the pressure from the environment must decrease as well in order to remain in balance. Outcomes for individuals are dependent upon the strength of environmental pressure in relation to an individual s adaptation level and his or her competence. The less competent the individual is, the greater the impact of environmental factors is on that individual (Lawton & Nahemow 1973). The outcome, when a person of a given level of competence is acting in an environment with a given pressure level, could be placed on a continuum from positive to negative and is manifested on two levels, as behaviour and affect. Thereby it would be possible to predict behavioural outcomes by looking at an individual s competence in relation to environmental pressure. There have been several studies using the ecological model as a framework for nursing actions in adapting the environment to patients needs. Reduction of environmental pressure by modification of the environment Reducing the environmental pressure to meet the normal sensory physiological changes that occur during the life-span has been the focus of multidisciplinary interest by both researchers and practitioners over the years (Cannava 1994, Pastalan 1997, Wijk 2001, Ulrich 2012). The impact of the environment on health and wellbeing is also one of the hallmarks of many nursing theories (Nightingale 1969, Watson 1985). The disease process itself affects the level of individual competence and most likely also the ability to handle the environmental press. Common changes in, for example, sensory acuity, psychomotor speed, mobility, social roles during illness and cognitive deterioration, make us more reliant on the physical environment when we are ill. This could be expressed as difficulties to acquire and retain spatial-bound information and to recognize features. It has been assumed that a supportive environmental layout could have a positive impact on behaviour despite loss of functions (Lawton 1994). Also studies within the architectural field are concerned about what demands a health promoting, patient focused perspective puts on the planning and design of hospitals (Dunlop 1993). It is therefore time to take a trans-disciplinary approach when working with the health care environment and being aware of the impact of the environment upon the quality of care. By doing so the team-work may be instrumental in reducing some of the harmful effects of a negative environmental design. The focus is on how to maximise the use of the residents capacities in the environment with the aim of finding a means to compensate for normal and pathological specific loss of function in the individual. For example, collaboration between architecture and nursing could be expanded when planning for new institutions so as to promote a better understanding of the special needs of the residents. Evaluation of the individual s personal competence should lead to different approaches in order to adapt the environmental pressure and promote independent functioning. Colour in the environment Colours are of great importance for most people in most environments for the detection and identification of objects, for information, and for the aesthetic point of view. Normally the perceptual information of the environment is sufficient, but visual and cognitive deterioration can have a negative impact on how we perceive and act in the environment. Wijk (2001) offers guidelines on how to use colours in the environment based on research and experiments with patients and controls. The importance of using colour contrasts to increase visibility, colour coding and cueing to support object identifica- 69

72 tion and a conscious colour scheme to make the environment attractive is emphasized. In addition Cooper et al (1999) have been able to demonstrate that neutral colours and lack of contrast minimise attention contrary to strong colour cues, which seems to attract attention. The former is suggested to prevent undesirable behaviour such as walking into restricted areas, the latter is suggested to as means of improving the visual distinction of environmental objects especially for low-vision subjects and as a mnemonic device. It is important to integrate evidence-based results such as those mentioned above in the health care environment, in order to prevent differences between the level of adaptation and demands posed by the surroundings in line with the model of Lawton (1973). We propose a more frequent use of contrasting colours in order to accomplish visual distinction in the environment, to support depth and spatial perception and to simplify object recognition (Wijk 2001). Colours similar in lightness could be juxtaposed when the purpose is to camouflage and minimise attention. Shades of different lightness within the red and yellow colour area on the walls of the room could support spatial distinction. Coding and cueing presuppose a communication between the carer and resident based upon a common opinion of the concept. Therefore we recommended a more frequent use of the elementary colours (blue, red, green, yellow, black and white) for codes and cues. Due to the often declining vision following old age, very dark colours should not be situated next to each other since they seem to be difficult to distinguish, and the same goes for very light colours. Since colour preferences remain more or less stable throughout life and since colour and colour design are highly appreciated among most people it is indicated that the colour scheme of health care environments ought to take a greater advantage of this than is common today. It is also suggested that colour could be used to attract attention of cues in the environment of the elderly. To support recognition in the long run, the shape of the cue and its associations seems to be more important. From this follows, that in order to make the patients be aware of the cues they have to be communicated between carers and resident, and they have to be clearly visible in the environment. Despite the evidence-based recommendations mentioned above (Wijk 2001) there have not been all that many systematic attempts to evaluate the advantages of a clear colour design in health care environments. Illumination of the environment It is quite common with insufficient illumination in health care environments which unnecessarily can have a negative effect on quality of life (Brunnström et al 2004). For patients cared for in their private homes the most important action is to change or complement the existing illumination with a better and more functional quality. This requires knowledge and a consciousness of good products from the dealer. Institutions are often lacking in variation and flexibility considering the illumination. In the dining room an illumination that both support activities and gives a nice atmosphere is needed such as a good lamp focusing both on the table and food which is crucial for independence during the meal (Bowers et al 2001). Also in the emergency unit illumination is a crucial factor for safety and quality of care. A high degree of exposure to daylight has proved to reduce depression and length of stay as well as to reduce perceived pain and need of analgesics (Golden et al., 2005, Beauchemin and Hays, 1996; 1998; Benedetti et al., 2001, Walch et al., 2005). It is also well known that there is a relation between a higher degree of exposure to daylight and an increased quality of sleep among the patients (BaHamman, 2006; Wakamura and Tokura, 2001). The exposure to daylight has also shown to have important positive effects on staff well-being, job satisfaction and attention (Rhea, 2004, Mrockzek et al., 2005, Alimoglu and Donmez, 2005) as well as decreasing stress (Verderber and Reuman, 1987). Also during night shift the quality of illumination and variation in light intense is important with positive effects on attention, adaption and quality of sleep (Baehr et al., 1999; Horowitz et al., 2001). When it comes to avoiding adverse events in health care, illumination can have an impact. A well adapted illumination has shown to decrease errors in medication by 37 % during high illumination (1500 lux) compared to during normal/ low illumination (450 to 1000 lux) (Buchanan et al., 1991). How to evaluate the impact or usefulness of environmental factors An overview of the existing amount of studies of health care environmental design reveals a lack of as well experimental as longitudinal studies in this field and the use of a variety of methods for evaluating the outcome. One of the reasons could be, as pointed out by Lawton (2001), that many environmental assessment instruments comprise of descriptive material that does not easily fit into an evaluative framework that determines how well a design element performs in meeting user needs. That is, beside the needs of the residents, of course also special needs of the staffs well-being such as their general health, anxiety, depression, quality of life, guilt and grief, job-satisfaction, and attitudes towards care (Skea and Lindsay 1996). Research strategies for evaluating the effect of environmental design in health care settings are for example consu- 70

73 NORDIC LIGHT & COLOUR mer surveys, direct behaviour observation, expert judgements or experimental design and environmental trials. The logic of using consumer surveys for evaluation is clearly to ask the experts, the residents and staff, with all their experience of staying in different types of health care settings, to assess the quality of care and the context of care. The limitation of this method is primarily due to that most existing questionnaires are quite complex in nature with a lack of focusing on environmental items. For most of the instruments presented in the literature the most necessary prerequisite needed before rating is a thorough training period of the persons in charge to use them. It needs to be pointed out that also when using a more qualitative design a systematic approach is necessary. This includes a specific definition of outcomes and how they fit user needs, the use of evidence based and best-practise knowledge from the literature together with the opinions of a reference group, and a step-by-step guidance for the observer task of documenting desired and non-desired behaviours and design evaluations. Nevertheless the outmost impact factor belong to studies that adapt the randomized controlled experimental study design including two or more environmental alternatives, with participants randomized into two groups, specific outcome variables documented in advance, and where data gathering is done through reliable and validated tests, observations and ratings herefore the on-going attempts of constructing specific evidence-based questionnaires facing the needs of various users of the environment including the patient, significant others and the staff, are most welcome and promising (Elf et al 2012). Future directions Caring sciences including both medical and nursing sciences are often considered as clinical sciences, with the primary aim of fighting against disease and promoting health. It is nevertheless evident that these two goals are closely related to each other since evidence-based facts derived from basic research ought to be essential for the more practical clinical science. However, the way basic results are implemented in clinical practise is determined by the values and ethical considerations currently prevalent in the society. This essay high-light some issues to consider during the design process of health-care institutions, which, if implemented in the environment, are of importance for residents function and well being. A prerequisite for a design that meets users needs is a tight collaboration between representatives of all the groups involved from the start. That is the residents themselves together with their family members, the staff, the managing directors, architects, designers, researchers in the field and experts on specific aspects of the environment such as colour design, illumination, ventilation and gardening. During the analysis the different perspectives are weighted against each other to conclude upon the summarized effect of the intervention. References Alimoglu, M. K. and Donmez, L. (2005). Daylight exposure and other predictors of burnout among nurses in a university hospital. International Journal of Nursing Studies, 42(6), Antonovsky A. Unravelling the mystery of health. How people manage stress and stay well. London: Jossey-Bass Publishers, Baksi A, Cradock S. What is empowerment? IDF Bulletin 1998; 3 (43): Baehr, E., Fogg, L. F., and Eastman, C. I. (1999). Intermittent bright light and exercise to entrain human circadian rhythms to night work. American Journal of Physiology, 277, BaHammam, A. (2006). Sleep in acute care units. Sleep and Breathing, 10(1), Beauchemin, K. M., and Hays, P. (1996). Sunny hospital rooms expedite recovery from severe and refractory depressions. Journal of Affective Disorders, 40(1 2), Beauchemin, K. M., and Hays, P. (1998). Dying in the dark: Sunshine, gender and outcomes in myocardial infarction. Journal of the Royal Society of Medicine, 91, Benedetti, F., Colombo, C., Barbini, B., Campori, E., and Smeraldi, E. (2001). Morning sunlight reduces length of hospitalization in bipolar depression. Journal of Affective Disorders, 62(3), Bowers, A. R., Meek, C., Stewart, N. (2001). Illumination and reading performance in age-related macular degeneration. Clinical and Experimental Optometry. 84,3, Brunnström, G., Sörensen, S., Alsterstad, K., Sjöstrand, J. (2004) Quality of Light and Quality of Life The effect of lighting adaptation among people with low vision. Ophthalmic and Physiological Optics 24. Buchanan, T. L., Barker, K. N., Gibson, J. T., Jiang, B. C., and Pearson, R. E. (1991). Illumination and errors in dispensing. American Journal of Hospital Pharmacy, 48(10), Cannava E. Gerodesign: Safe and comfortable living spaces for older adults. Geriatrics, 1994; 49(11):

74 Cooper BA. The utility of functional colour cues: seniors views. Scandinavian Journal of Caring Sciences, 1999;13(3): Curtis, S. Gesler, W. Priebe, S. & Francis, S. (2009). New spaces of inpatient care for people with mental illness: a complex rebirth of the clinic? Health & Place, 15, Dunlop A. Hard architecture and human scale designing for disorientation, a litterature review on designing environments for dementia. Dementia services development centre. Department of applied social science, School of human sciences, University of Stirling, Ekman, I, Swedberg K, Taft C, Lindsteth A, Norberg A, Brink E, Carlsson J, Dahlin-Ivanoff S, Johansson I-L, Kjellgren K, Lidén E, Öhlén J, Olsson L-E, Rosén H, Rydmark M, Stibrant Sunnerhagen K. Person-centered care Ready for prime time Eur J Cardiovasc Nurs Dec;10(4): doi: /j.ejcnurse Epub 2011 Jul 20. Elf, M. Svedbo Engström, M. and Wijk, H. (2012) Development of the Content and Quality in Briefs Instrument (CQB-I). Journal of Health care Environment Research and Development. HERD, 5 (3) Gesler, W. Bell, M. Curtis, S. Hubbard, P. and Francis, S. (2004) Therapy by design:evaluating the UK hospital building program. Health & Place, 10, Golden, R. N., Gaynes, B. N., Ekstrom, R. D., Hamer, R. M., Jacobsen, F. M., Suppes, et al. (2005). The efficacy of light therapy in the treatment of mood disorders: A review and meta-analysis of the evidence. American Journal of Psychiatry, 162(4), Horowitz, T., Cade, B., Wolfe, J., and Czeisler, C. (2001). Efficacy of bright light and sleep/darkness scheduling in alleviating circadian maladaption to night work. American Journal of Physiology Endocrinology and Metabolism, 281, Küller R. Familiar design helps dementia patients cope. In: WFE. Preiser, JC. Vischer, ET. White (eds) Design Intervention. Toward a more Humane architecture. New York, Van Nostrand Reinhold. 1991: Lawton MP, Nahemow L, Ecology and the aging process. In: C. Eisdorfer, MP Lawton eds. The psychology of adult development and aging. American Psychological Association, Washington DC, 1973: Lawton M.P. Quality of life in Alzheimer s disease. Alzheimer s Disease and Associated Disorders, 1994; 8, suppl. 3: Lawton M.P. (2001) The physical environment of the person with Alzheimer s disease. Aging and Mental Health, 5 (Supplement1):S Liebowitz B, Lawton MP, Waldman A. Evaluation: Designing for confused people. American Intern. Alzheim. J. 1979: Mroczek, J., Mikitarian, G., Vieira, E., and Rotrius, T. (2005). Hospital design and staff perceptions. The Health Care Manager, 24(3), Nightingale F. Notes on nursing. New York: Dover publications. (Original 1860) Orem D. Nursing Concepts of practice. Fifth ed. New York: Mosby-Year Book Inc Passini R, Pigot H, Rainville C, Tétreault M-H. Wayfinding in a nursing home for advanced dementia of the Alzheimer s type. Environment and behaviour. 2000; 32(5): Passini R, Rainville C, Marchand N, Joanette Y. Way finding and dementia: some research findings and a new look at design. Journal of architectural and planning research 1998;15:2: Pastalan LA. Shelter and service issues for aging populations. International perspectives. The Haworth Press, Inc. New York, Rea, M. (2004). Lighting for caregivers in the neonatal intensive care unit. Clinical Perinatology, 31, Skea, D., and Lindsay, J. (1996). An evaluation of two models of long-term residential care for elderly people with dementia. International Journal of Geriatric Psychiatry, 11, Ulrich R.S Evidence-based health care architecture, Lancet; 368, 38-39, Ulrich, R Evidence for health care architecture 1.0 Research that supports the design of the physical care environment (in Swedish) Evidensbas för vårdens arkitektur 1.0 Forskning som stöd för utformning av den fysiska vårdmiljön. Centrum för Vårdens Arkitektur, Publikation /2012, Chalmers Tekniska Högskola: Göteborg Verderber, S., and Reuman, D. (1987). Windows, views, and health status in hospital therapeutic environments. Journal of Architectural & Planning Research, 4(2), Vischer, J. (2008) Towards a user-centred theory of built environment. Building Research and Information, 36, Wakamura, T., and Tokura, H. (2001). Influence of bright light during daytime on sleep parameters in hospitalized elderly patients. Journal of Physiological Anthropology and Applied Human Science, 20(6), Walch, J. M., Rabin, B. S., Day, R., Williams, J. N., Choi, K., and Kang, J. D. (2005). The effect of sunlight on post-operative analgesic medication usage: A prospective study of patients undergoing spinal surgery. Psychosomatic Medicine, 67, Watson J. Nursing: Human sciences and human care. A theory of nursing. New York: National league for nursing, 1985 Wijk, H., Colour perception in old age. Colour discrimination, colour naming, colour preferences and colour/shape recognition. Doctoral thesis Gothenburg University, 2001b. 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75 NORDIC LIGHT & COLOUR DAYLIGHTING SCIENCE: A BRIEF SURVEY AND SUGGESTIONS FOR INCLUSION IN THE ARCHITECTURAL CURRICULUM John Mardaljevic ABSTRACT Daylight has always been a key consideration for architects, albeit one where the skills for effecting good daylighting design were more art than science. Until recently however daylight was something of a Cinderella discipline as far as the wider building engineering community were concerned. That is, generally well-regarded, but not taken too seriously. That has has changed in the last decade or so with a deeper understanding of the benefits to occupants provided by a well-daylit environment. New methods of quantifying and evaluating the daylighting provision of a space has led to a reconsideration of the way that daylighting science is taught to architecture students. This article is intended to contribute to that discourse. 73

76 Daylight Sunlight Skylight Direct sunlight Indirect sunlight Direct skylight Indirect skylight 'Direct' light 'Diffuse' light Daylight in buildings Figure 1: Components of daylight illumination in buildings 74

77 NORDIC LIGHT & COLOUR Introduction Daylight in buildings is the natural illumination experienced by the occupants of any man-made construction with openings to the outside, e.g. dwelling, workplace, etc. The quantity and quality of daylight in buildings is continually varying due to the natural changes in sun and sky conditions from one moment to the next. These changes have components that are: random (e.g. individual cloud formations); daily (i.e. progression from day to night); and, seasonal (e.g. changing day length and prevailing weather pat- terns). For any given sky and sun condition the quantity and character of daylight in a space will depend on: the size, orientation and nature of the building apertures; the shape and aspect of the building and its surroundings; and, the optical (i.e. reflective and transmissive) properties of all the surfaces comprising the building and its surroundings. Daylight may arrive at a point inside a building either directly or indirectly from the luminous source, i.e. from the sun or from the sky. Direct illumination generally results from having an unobstructed view of the source. Indirect illumination is when the light arrives at the point following one or more reflections. Thus, strictly speaking, there are direct and indirect components of illumination from both the sun and the sky, Figure 1. Although the sun and the sky are both luminous sources, direct sunlight when present is given special consideration because of the small angular size of the sun and its potentially large contribution to illumination (and also its heating effect). Thus illumination from direct sunlight is commonly referred to as direct light. In contrast, light from the sky - arriving either directly or indirectly - is commonly referred to as diffuse light. Sunlight that has undergone one or more diffuse reflections is also commonly referred to as diffuse light. Note, the mode of reflection of the direct sunlight is important: a specular (or mirror ) reflection of sunlight will produce a redirected beam of direct light rather than diffuse light. For reflections (and transmissions) that are part-specular and part-diffuse, the distinction between direct and diffuse light can become lost. Reflections can occur either internal or external to the building space under consideration. The purpose of the very earliest shelters the forerunners of buildings was to protect from the elements. The first buildings to include deliberate elements of daylighting design were often places of worship, many of which survive to this day. Only when glass became relatively commonplace in the 17th century did the provision of daylight for everyday buildings become a consideration. Window design was invariably tailored to the prevailing climate, e.g. small with deep reveals for locales where the solar component of daylight needed to be controlled to prevent overheating. As the cities of the industrialised world became more populous, building densities increased and the provision of daylight for buildings became a planning issue. This eventually resulted in the formulation of the daylight factor which was intended to be a measure of the daylighting potential of a building, and which could be predicted at the design stage using a variety of methods (Hopkinson et al., 1966). Devised in the first half of the 20th century, the daylight factor still forms the basis of many guidelines and recommendations for building design. It is discussed in details in a later section. Advances in glass making and window technology in the second half of the 20th Century allowed architects to design buildings where the perimeter wall could be almost entirely glazed. Commercial buildings in particular became larger with deeper plan de- signs so that, despite the highly transparent facade, many occupants were situated far from the windows and so received little daylight. A conspicuous icon symbolising modernity and prosperity, these designs became the exemplars for architects all over the world, and now many cities feature highly-glazed buildings regardless of the local climatic conditions. Thus the daylighting characteristics of office buildings in particular tended to be dictated by considerations of architectural style rather than climate-adapted design. These trends were not hindered by the continued reliance on the daylight factor as an evaluative scheme since the measure is itself climate and orientation insensitive. For the majority of buildings it is incumbent on the occupants to moderate the internal daylight conditions using some form of blinds or shades. Occupants will deploy blinds/shades in an effort to moderate the internal environment according to their perceptions of both visual discomfort (e.g. daylight glare) and thermal discomfort (e.g. to avoid direct sun) which vary greatly from person to person. Also, once deployed, blinds/shades will tend to remain closed long after the external condition has passed. Thus it is common to see blinds closed for much of the occupied time. Consequently, the potential to exploit daylighting is often not realised because the blinds are left closed most of the time and the electric lights are left switched on. Towards the end of 1990s, the daylighting of buildings began to achieve greater atten- tion for a number of reasons. The two most important drivers were: 1. the widespread belief that the potential to save energy through effective daylighting was greatly under-exploited; and, 2. the emergence of data suggesting that daylight exposure has many positive produc- tivity, health and well-being outcomes for building occupants. 75

78 The first originated with the widely-accepted need to reduce carbon emissions from buildings in order to minimise the anticipated degree of anthropogenic climate change. This in turn led to the formulation of guides and recommendations to encourage the design and construction of low energy buildings and also for the retrofit of existing buildings. All these guides contain recommendations on daylighting, invariably founded on the daylight factor or an equally simplistic schema such as glazing factors. The non-visual productivity, health and well-being effects related to daylight exposure are not yet fully understood, and it is not yet known what the preferred exposure levels should be, nor if existing guidelines would be effective for these quantities. Almost concurrent with the emergence of the two key drivers noted above were a major advance in the way daylight in buildings could be modelled; and, the development of numerous new glazing systems and materials to better exploit daylighting in buildings. These developments are expected to lead to significant changes in the way that daylight in buildings is both evaluated (through modelling) and exploited (by new glazing systems and materials). New developments always pose new challenges. At the time of writing, it is not yet clear how these new developments will be accommodated within teaching in architecture and engineering. This article is intended to contribute to that discussion. Guidelines for daylighting One of the earliest recorded recommendations for climate-adapted building design is that attributed to Socrates [ BC]: Now in the houses with a south aspect, the Sun s rays penetrate into the porti- coes in the winter, but in summer, the path of the Sun is right over our heads and above the roof so that there is shade. If, then, this is the best arrangement, we should build the south side loftier to get the winter sun and the north side lower to keep out the cold winds. Quoted by Xenophon in Memorabilia Socrates Over the following two thousand years numerous architectural styles evolved across the globe in response to the specific cultural/societal imperatives and driven by advances in building technology and construction techniques. Daylighting design remained a rule-of- thumb practice, informed by tradition and internalised knowledge about what was known to work for that particular climate and locale. Building apertures were rarely designed for the sole purpose of providing daylight illumination since protection from the hot and cold extremes of the prevailing climate was often the key design concern. The pressure to accommodate increasing number of people in cities of the developing world in the late 1800s led to taller and more tightly-packed building forms, thereby reducing and often eliminating entirely the direct view of sky from much of the useable, internal space. This in part led to the need for some objective measure of the daylighting performance of a space which could, if required, function as a tool to evaluate buildings at the planning stage. Daylight was at that time still the preferred source of illumination for both manual and clerical work. Illuminance for Task The absolute levels of illuminance that are needed for any particular task depends on the visual acuity required for the task and, to a lesser degree, the nature of the environment in which the task is to be carried out. Most developed countries have produced design guides which give recommended illuminance levels depending on task and/or setting. The following is a selection of recommendations produced by the British Chartered Institution of Building Services Engineers (CIBSE) (CIBSE Guide A, 2006): 100 lux for interiors used rarely, with visual tasks confined to movement and casual seeing without perception of detail, e.g. corridors, changing rooms, bulk stores, auditoria. 200 lux for interiors where the visual tasks do not require perception of detail, e.g. foyers and entrances. 300 lux for interiors where visual tasks are moderately easy, e.g. libraries, sports and assembly halls, teaching spaces, lecture theatres. 500 lux for interiors where the visual tasks are moderately difficult and also where colour judgement may be required, e.g. general offices, kitchens, laboratories, retail shops lux for interiors where the visual tasks are very difficult, requiring small details to be perceived, e.g. general inspection, electronic assembly, retouching paintwork, cabinet making, supermarkets. Recommended illumination levels were conceived primarily for the purpose of designing artificial lighting systems, and not for the daylighting design of buildings because the variation in the provision of natural daylight is such that it is virtually impossible to deliver specific natural illumination levels without huge fluctuations occurring. For buildings therefore, design guidance was formulated in terms of building properties which are evaluated under a single, static worst-case daylight condition: an overcast sky. This is the basis of the daylight factor described in following section. It is only with recent advances in daylight prediction techniques that absolute levels of daylight illumination under varying sky and sun conditions has become a consideration in the evaluation of the daylighting potential of a building. 76

79 NORDIC LIGHT & COLOUR The Daylight Factor Design guidelines worldwide currently recommend daylight provision in terms of the longestablished daylight factor (DF) (Hopkinson, 1963). It appears that the daylight factor, or at least its precursor, was first proposed in 1895 by Alexander Pelham Trotter ( ) (Love, 1992). The origins of the daylight factor are actually somewhat hazy since there does not appear to have been a seminal paper introducing the approach. The reference to its introduction in 1895 appears to be anecdotal and recalled a number of years later. The daylight factor was conceived as a means of rating daylighting performance independently of the actually occurring, instantaneous sky conditions. Hence it was defined as the ratio of the internal horizontal illuminance E in to the unobstructed (external) horizontal illuminance E out, usually expressed as a percentage, Figure 2: However, the external conditions still need to be defined since the luminance distribution of the sky will influence the value of the ratio. At the time that the daylight factor was first proposed it was assumed that heavily overcast skies exhibited only moderate variation in brightness across the sky dome, and so they could be considered to be of constant uniform) luminance. Measurements revealed however that a densely overcast sky exhibits a relative gradation from darker horizon to brighter zenith; this was recorded in With improved, more sensitive measuring apparatus, it was shown that the zenith luminance is often three times greater than the horizon luminance for some of the most heavily overcast skies (Moon and Spencer, 1942). A new formulation for the luminance pattern of overcast skies was presented by Moon and Spencer in 1942, and it was adopted as a standard by the International Commission for Illumination (CIE) in Normalised to the zenith luminance L Z, the luminance distribution of the CIE standard overcast sky has the form: where is the luminance at an angle from the horizon and L Z is the zenith luminance (Figure 2). The luminance of the CIE standard overcast sky is rotationally symmetrical about the vertical axis, i.e. about the zenith. In other words, the illumination that the standard overcast sky delivers to an internal space will be same regardless of the compass orientation of the building. And, since the sky is fully overcast, there is no sun. Thus for a given building design, the predicted DF is insensitive to either the building orientation (due to the symmetry of the sky) or the intended locale (since it is simply a ratio). Because the sun is not considered, any design strategies dependant on solar angle, solar intensity, or redirection of sunlight can have no influence on the daylight factor value. Dissatisfaction with the standard guidelines Many guidelines give an average daylight factor as the recommended target. For exam- ple, in BS the guidance states that to have a predominantly daylit appearance... [the] average daylight factor should be at least 2% (BSI, 2008). In a similar vein, the Building Research Establishment Environmental Assessment Method (BREEAM) states that... at least 80% of floor area in occupied spaces has an average daylight factor of 2% or more. 1 These guidelines can have a major influence on key aspects of the building design. For example, school buildings with a significant element of prefabrication have been designed to conform to BREEAM daylight specifications, Figure 3 (Jansen, 2011). Note however that, even with something as seemingly straightforward as an average daylight factor specification, the results are open both to interpretation and gameplaying. The average can be a quite misleading quantity when applied to daylight dis- tributions, especially for spaces illuminated from vertical glazing on one wall where the very high DFs close to the windows can significantly influence the average DF value. The 2011 revision of Lighting Guide 5: Lighting for Education recommends that there is a 0.5m border width (i.e. perimeter) between the sensor points and the walls/glazing (LG5 CIBSE/ SLL, 2011). However, note that LG5 is stated in terms of a border, whereas the BREEAM guidance recommends a percentage of the floor area for the sensor points, but not where it should be placed. Thus, with BREEAM, the user could in principle choose where to place the 80% coverage sensor plane leading to significant variation in the outcome. An 80% coverage sensor plane pushed-up against the glazing would result in a markedly higher average DF compared to one that was centrally placed, and greater still compared to one placed at the rear of the space. The median DF would be far less sensitive to such placement issues (Mardaljevic, 2013). The impossibility of holistic daylighting design with a fractured methodology In the half-century or more since the daylight factor was first formulated it has become the the dominant metric, in fact, often the sole quantitative measure of natural illumination used to evaluate building designs. An indication perhaps of the ubiquity of the daylight factor is its appearance as a measure 77

80 t factor E out L z Zenith E in L Daylight factor CIE standard overcast sky pattern L h horizon Figure 2: Definition of the daylight factor and the CIE standard overcast sky June 2011 OUT OF THE BOX IS IT TIME TO THINK ABOUT A FLAT-PACKED FUTURE FOR BUILDING? HOUSING SPECIAL Innovations in new builds and retrofits LIGHTING GUIDE Lessons for school environments ELECTRICAL SERVICES Benefits of taking a whole-life approach Figure 3: Prefabricated school building with classrooms designed to BREEAM daylight factor specification [from CIBSE Journal, June 2011] 78

81 NORDIC LIGHT & COLOUR for compliance in the most unexpected places. The daylight evaluation in the first edition of the Estidama Pearls Design System for Abu Dhabi was founded on daylight factors, i.e. the CIE standard overcast sky (Estidama, 2009). A quick examination of the standard climate for Abu Dhabi reveals that it is almost never overcast in that region of the United Arab Emirates. This, not unexpected observation, suggests that at least in some instances the daylight factor has indeed been applied as a matter of routine without consideration of the prevailing climatic conditions. As noted in the Introduction, it is in fact the non-energy related considerations of daylight that are likely to have the greatest influence on building design in the future. The studies that have claimed improved academic achievement for, say, classrooms with good daylighting have gained prominence in design circles and are now influential when fundamental decisions regarding performance criteria are made (Heschong, 2002). But, whilst the message regarding good daylighting is being taken notice of, the implementation is often poor if not actually counterproductive that is, it could result in worse rather better daylight performance. In part this occurs because good daylighting is often taken to mean more daylight, which in turn is taken to mean higher daylight factors. In practice, this often results in spaces where the occupants habitually lower blinds/ shades to control for visual and/or thermal discomfort any daylight benefit is lost and the lights are usually left switched on. Such outcomes should not be too surprising because reliance on the daylight factor has not encouraged practitioners to think of the luminous environment as one that should be well-tempered, i.e. avoiding too much as well as too little. Consider the following two criteria taken from the Construction Requirements for a UK hospital: minimise direct solar gain to avoid the requirement for air conditioning / comfort cooling; maximise daylight factor in patient areas; Using the standard toolset i.e. daylight factors and solar penetration / heat gain study, these two criteria are impossible to reconcile. Hardly surprising since one method uses a (single) sunless sky and the other a skyless sun, Figure 4. The marginalisation of the expert daylight designer A half-century or more of often uncritical use of the DF has unfortunately led to a conflation in many minds of actual daylighting performance with what the daylight factor tells us. The DF is of course a proxy for daylight, but how good or bad a proxy depends on those important parameters that the DF approach cannot account for: prevailing climate (meaning the totality of sky and sun conditions) and building/site orientation. The expert daylight designer does of course appreciate these intrinsic deficiencies. If sufficiently experienced, the designer can roughly guesstimate the likely daylighting performance of the space and so recommend suitable facade treatments to temper the luminous environment. Thus the expert intuits what is called the spatio-temporal dynamics of natural illumination. We of course shouldn t be surprised to learn that the designer recommends different treatments for the north, south and east/west elevations. Nor that the advice would change if the building were relocated from, say, Stockholm to Madrid. After all, climate-adapted design is a notion that relates closely to vernacular architecture. The designer will probably also carry out a daylight factor analysis because it is easy to do and they can charge the client for it even if they take minimal notice of it themselves. If however the client demands that the daylight credit from a particular guideline document (e.g. BREEAM, LEED 2, etc.) must be achieved, then the success of the design will hinge to a large degree on the nature of the target sought - invariably some measure based on the daylight factor. In which case, the best the expert designer can do is try to make good the failings that might, and often do, result from compliance chasing. The client may even decide that the expert is not required since the facade treatment will be optimised by someone using a lighting simulation tool: tweaking here and there until the compliance target is reached. This has led one notable lighting expert to conclude that:... the only people who have a chance of getting it right are those who ignore everything the lighting profession proclaims through daylighting codes, stan- dards and recommended practice documents. (Cuttle, 2012) Such sentiments are understandable. However, if the standards are proving to be insufficient to ensure a high likelihood that a good daylighting design is achieved, then we should look to improving them rather than ignoring or ditching them altogether. The Daylight Factor and Actual Daylighting Conditions The daylight factor was formulated long before the computation of actual illumination levels became a practical possibility. Thus the simplifications inherent in the formulation were back then a necessary expediency. Also, it was believed that the daylight factor expressed the efficiency of a room and its window(s) as a natural lighting system because humans perceive relative rather than absolute luminances. In other words, the daylight factor provides a better indicator of the luminous environment experienced by humans than absolute illuminances because it expresses the amount of light in a space relative to the light that would be seen outdoors in sidelit spaces (Hopkinson et 79

82 Daylight factor Solar shading Incompatible methodologies - often giving contradictory advice Direct sky Figure 4: Incompatible methodologies often giving contradictory advice Direct sun Direct sky Direct sun Indirect Indirect sky sky 10,000 nance lux Indirect Indirect sun sun 1, Figure 5: Daylight simulation for a simple space under clear sky conditions with sun. 80

83 NORDIC LIGHT & COLOUR al., 1966). The argument has some credence, however on its own it fails to address the patently obvious fact that humans also require that illumination be within absolute levels in order to carry out various tasks, to safely negotiate hazards, etc. Another major issue with the daylight factor is that actual daylight illumination conditions deviate markedly from that described by the overcast sky paradigm. This is so even for Northern Europe where there is a commonly held belief that skies are mostly overcast and so use of the daylight factor as a basis for evaluation is justified. A paper by Littlefair in 1998 gives annual cumulative internal illuminance measurements for a point in similar rooms with North and South facing glazing (Littlefair, 1998). The rooms were un-shaded and un-occupied. An illuminance of 200 lux was achieved for approximately 58% and 68% of the year for the North and South facing spaces respectively. However, an illuminance of 400 lux was achieved for only 12% of the year for the North facing space with more than four times that occurrence (51%) for the South facing space. Of course, for sunnier climates the effect of orientation on daylight illumination will be greater still. An unfortunate consequence of the long-standing and often uncritical use of the daylight factor is that the terms daylight (as defined in the Introduction) and skylight are often used interchangeably. This leads to confusion where precise definitions are required. Some of this muddle has resulted from the conflation of daylight per se with what is predicted by the daylight factor. For example, expressions such as: the daylight factor was used to evaluate daylight levels, are common in both research and practice literature. The daylight factor is precisely what it was defined to be: a ratio of illuminances under a specific sky condition. The daylight factor therefore is, in reality, a proxy for actual daylight illumination. Thus what the daylight factor communicates is in fact very different from the actual illumination levels that result from the full range of naturally occurring sun and sky conditions. Extending the basis of the daylight factor approach by incremental means has proved problematic. It is a straightforward matter to use in a daylight simulation non-overcast sky conditions, for example, the CIE clear sky luminance pattern with sun, Figure 5. The inset images show the illuminance for the four components of daylight illumination as described in Figure 1. These images reveal the complexity of illumination that ex- ists in even the simplest of spaces under realistic daylight conditions. To be useful for evaluation purposes however, the luminous output of the sun and sky must be known since absolute values and not ratios must be considered. Extending the daylight factor notion of ratios to non-overcast skies with sun results in essentially meaningless values and should be avoided. When absolute values for luminous quantities are predicted (e.g. lux at the work plane) then the values used to normalise the output from and sky must be justified, e.g. diffuse horizontal illuminance for the sky and direct normal illuminance for the sun. Ideally, these should be based typical values for, say, a clear, sunny day in summer. The predicted quantities however will be of very limited value for any estimation of prevailing daylight levels in the building since they are indicative only of conditions for particular sun and sky conditions occurring at a particular time of the day/year. In other words, such an evaluation would offer merely a single snapshot of the multitude of naturally occurring daylight conditions due to all the possible combinations of sun and sky conditions occurring at various times throughout the year. Estimating overall daylighting performance from snapshot evaluations could be highly misleading. The parameters governing the availability of daylight do not lend themselves to any form of averaging. Whilst it can be informative to determine, say, a monthly average for a scalar quantity such as temperature, illumination is strongly dependent on the directional character of the incident light. Associated with every non-overcast sky and sun condition are the solar altitude and azimuth which, of course, vary continuously throughout the day. In terms of providing a basis for predicting measures of illumination, the notion of average days is less than useful because an average sun position would give entirely misleading patterns of illumination. The true nature of illumination from the sun and sky for any particular locale can only be appreciated by examining the luminous output from both the sun and the sky over a period of a full year. The principal sources of annual climate data are the standard weather files which were originally created for use by dynamic thermal modelling programs (Clarke, 2001). These datasets contain averaged hourly values for a full year, that is, 8760 values for each parameter. The key daylight parameters stored in the weather files are the diffuse horizontal illuminance and the direct normal illuminance. The diffuse horizontal illuminance is the visible part of the radiant energy from the unobstructed sky that is incident on a horizontal surface. The direct normal illuminance is the visible light energy from the sun that is incident on a surface which is kept normal to the beam of radiation, i.e. the photocell always points directly to the sun. A visualisation of the illuminance data from a standard weather file is given in Figure 6. The time-series data of 8760 values has been rearranged into an array of 365 days (x-axis) by 24 hours (y-axis). The shading at each hour indicates the magnitude of the illuminance see legend with zero values shaded grey. Presented in this way it is easy to appreciate both the prevai- 81

84 24 Diffuse Horizontal Illuminance SWE-Ostersund Hour Month lux 24 Direct Normal Illuminance Hour Month Figure 6: Illuminance data from the standard climate file for Ostersund, Sweden 82

85 NORDIC LIGHT & COLOUR ling patterns in either quantity and their short-term variability. Most obvious is the daily/seasonal pattern for both illuminances: short periods of daylight in the winter months, longer in summer. The hour-by-hour variation in the direct normal illuminance is clearly visible, though it is also present to a lesser degree in the diffuse horizontal illuminance (i.e. light from the sky). The data is for Östersund in northern Sweden the location of which is identified in the map above the legend. Local time is shown, i.e. summertime is local time plus one hour. The start and end period of summertime are indicated by vertical dashed lines in each of the figures. Recall the patterns of indoor illumination for the four components of daylight given in Figure 5. Each of the 4380 (i.e. the daylight hours) unique combinations of sky and sun conditions in the weather file (Figure 6) will result in a unique pattern of internal daylight illumination. Both diffuse and direct illuminances will, in reality, vary over periods much shorter than an hour. Interpolation of the dataset to a time-step shorter than one hour will provide a smoother traversal of the sun, which may be necessary when using the data for simulation of daylight. Interpolation alone however will not introduce short-term variability into the values for diffuse horizontal and direct normal illuminance. If required, this variability would have to be synthesised using stochastic models (Skartveit and Olseth, 1992). The illuminance data in the standardised weather files reveal the true nature of the patterns in daylight illumination from the sun and the sky. It is also evident from the visualisation of the data (Figure 6) that any snapshot evaluation using just part of the data would not be representative and could lead to highly flawed conclusions regarding the daylighting performance of the building. How these data might be used in their entirety to better predict actual building performance is described in the next Section. Climate-Based Daylight Modelling Climate-based daylight modelling is the prediction of various radiant or luminous quantities (e.g. irradiance, illuminance, radiance and luminance) using sun and sky conditions that are derived from standardised annual meteorological datasets. Climate-based modelling delivers predictions of absolute quantities (e.g. illuminance) that are dependent both on the locale (i.e. geographically-specific climate data is used) and the fenestration orientation (i.e. accounting for solar position and non-uniform sky conditions), in addition to the space s geometry and material properties. The operation of the space can also be modelled to varying degrees of precision depending on the type of device (e.g. luminaire, venetian blinds, etc.) and its assumed control strategy (e.g. automatic, by occupant, or some combination). The term climate-based daylight modelling does not yet have a formally accepted definition - it was first coined by the author in the title of a paper given at the 2006 CIBSE National Conference (Mardaljevic, 2006). However it is generally taken to mean any evaluation that is founded on the totality (i.e. sun and sky components) of time-series daylight data appropriate to the locale over the course of a year. In practice, this means sun and sky parameters found in, or derived from, the standard meteorological data files which contain 8760 hourly values for a full year (Figure 6). Given the self-evident nature of the seasonal pattern in sunlight availability, a function of both the sun position and the seasonal patterns of cloudiness, an evaluation period of twelve months is needed to capture all of the naturally occurring variation in conditions that is represented in the climate dataset. It is also possible to use real-time monitored weather for a given time period, if calibration to actual monitored conditions within a space is desired. In short, climatebased daylight modelling is the ability to predict daylight illumination (such as that shown in Figure 5) for all the hourly (or sub-hourly) sky and sun conditions in a climate file. There are a number of possible ways to use climate-based daylight modelling. The two principal analysis methods are cumulative and time-series. A cumulative analysis is the prediction of some aggregate measure of daylight (e.g. total annual illuminance) founded on the cumulative luminance effect of (hourly) sky and the sun conditions derived from the climate dataset. It is usually determined over a period of a full year, or on a seasonal or monthly basis, i.e. predicting a cumulative measure for each season or month in turn. Evaluating cumulative measures for periods shorter than one month is not recommended since the output will tend to be more revealing of the unique pattern in the climate dataset than of typical conditions for that period. The cumulative method can be used for predicting the micro-climate and solar access in urban environments, the long-term exposure of art works to daylight, and quick assessments of seasonal daylight availability and/ or the requirement for solar shading at the early design stage. Time-series analysis involves predicting instantaneous measures (e.g. illuminance) based on each of the hourly (or sub-hourly) values in the annual climate dataset. These predictions are used to evaluate, for example, the overall daylighting potential of the building, the occurrence of excessive illuminances or luminances, as inputs to behavioural models for light switching and/or blinds usage, and the potential of daylight responsive lighting controls to reduce building energy usage. Thus a daylight performance metric would need to be based on a time- 83

86 Figure 7: New York Times 3D model highly detailed office geometry nested in large- scale city model Figure 8: Images from the shoe-box lighting model 84

87 NORDIC LIGHT & COLOUR series of instantaneously occurring daylight illuminances since these cannot be reliably inferred from cumulative values. As noted, evaluations should span an entire year. There is some debate as to whether the daily time period of analysis should be all daylit hours, which vary in length with the seasons, a standardised working day of 8, 10 or 12 hours, or the actual occupancy pattern of the space. Different purposes are likely to favour different daily analysis periods. There are some long-standing daylight prediction methods that make use of climate data to estimate either instantaneous or cumulative illuminance. For example, the thermal simulation program DOE-2 has featured a daylight prediction module for over twenty years (Winkelmann and Selkowitz, 1985). These methods however do not explicitly simulate the transport of light in a space and instead employ various crude approximations. Furthermore, they are generally limited to very simple building geometry with basic material properties (Koti and Addison, 2007). In contrast, climate-based daylight modelling refers to techniques that use lighting simulation proper. Additionally, there should be few significant limitations on either the complexity of the building geometry or the properties of the reflecting and transparent materials used since high levels of realism are necessary to adequately simulate the daylit luminous environment for the majority of real building designs, e.g. Daylighting the New York Times Building (Lee et al., 2005) (Figure 7). Daylight Metrics A metric is some mathematical combination of (potentially disparate) measurements and/or dimensions and/or conditions represented on a continuous scale (Mardaljevic et al., 2009a). A metric may not be directly measurable in the field. A criteria is a demarcation on that metric scale that determines if something passes or qualifies, e.g. three-quarters of the workspace area achieves a 2% daylight factor. The purpose of a metric is to combine various factors that will successfully predict better or worse performance outcomes, and so inform decision making. Performance may be described by more than one metric, i.e. it is not necessary to combine all significant factors into one metric. The most useful metrics have an intuitive meaning for their users and can also be directly measured for validation. This implies a preference for simplicity so they can be intuitively understood, and a direct relation to measurable outcomes made. When metrics are sufficiently refined and understood and their predictive capabilities validated, then performance criteria can be set for various guidelines and recommendations. As has been noted, metrics founded on the daylight factor are relatively straightforward since there is no time-varying component and so they simply report on: the DF value at a point; some average DF value across a workplane; or perhaps some measure of uniformity of the DF across the workplane. Metrics founded on climate-based modelling are potentially far more complex since the simulations output illuminance data at each time-step for every point in the space. Thus, for all daylight hours in the year, a climatebased simulation would output approximately 4380 values for every calculation point considered. And potentially several times this number if the simulations were run at a shorter time-step to, say, better resolve the progression of the solar patch across the internal space. Various climate-based daylight metrics have been formulated since the emergence of climate-based modelling in the late 1990s. These metrics are being investigated by daylighting researchers in order to determine their potential to reliably characterise daylight in buildings for the purpose of discriminating between good, bad and mediocre de- signs (Reinhart et al., 2006) (Mardaljevic et al., 2009a). One of the more straightforward climate-based metrics is daylight autonomy (DA) (Reinhart and Walkenhorst, 2001). The DA metric determines the annual occurrence (within, say, working hours) of illuminances above a stated design level illuminance, e.g. 300 or 500 lux. Qualitatively, plots of DA appear similar to those for DFs since both are proportional to the available illuminance regardless of the external conditions (i.e. time-varying for climate-based and static, overcast for the daylight factor). It is well known however that occupants prefer day- light illumination not to exceed certain levels, although it is not clear what precisely those levels are since occupants vary in their responses. The useful daylight illuminance (UDI) metric was formulated as a means to reduce the voluminous time-series data from a climate-based simulation to a form that is of comparative interpretative simplicity to the daylight factor method, but which nevertheless preserves a great deal of the significant information content of the illuminance time-series. The UDI metric informs on the occurrence of illuminances in the range that occupants either prefer or tolerate together with the propensity for excessive levels of daylight that are associated with occupant discomfort and unwanted solar gain (Mardaljevic, 2006). Thus useful daylight illuminance is more firmly grounded on human factors than metrics which determine only sufficiency for task. Achieved UDI is defined as the annual occurrence of illuminances across the work plane that are within a range considered useful by occupants. The range considered useful is based on a survey of reports of occupant preferences and behaviour 85

88 Figure 9: Heliodon at NTNU, inset image shows light source to deliver wide-area parallel beam Figure 10: High dynamic range image of an outdoor scene 86

89 NORDIC LIGHT & COLOUR in daylit offices with user operated shading devices. Daylight illuminances in the range 100 to 500 lux are considered effective either as the sole source of illumination or in conjunction with artificial lighting. Daylight illuminances in the range 300 to around 2,000 or maybe 3000 lux are often perceived either as desirable or at least tolerable. The range limits for UDI depend to a degree on the particular application, and, at the time of writing, there is no consensus on what precise values the upper and lower range limits should have. Nonetheless, the UDI scheme combines intuitive simplicity with rich information content. For the example shown later in this article, UDI was defined as the annual occurrence of daylight illuminances that are between 100 and 3000 lux (PAGE REF). The UDI range is further subdivided into two ranges called UDI-supplementary and UDI-autonomous. UDI-supplementary gives the occurrence of daylight illuminances in the range 100 to 300 lux. For these levels of illuminance, additional artificial lighting may be needed to supplement the daylight for common tasks such as reading. UDI-autonomous gives the occurrence of daylight illuminances in the range 300 to 3000 lux where additional artificial lighting will most likely not be needed. The UDI scheme is applied by determining at each calculation point the occurrence of daylight levels where: The illuminance is less than 100 lux, i.e. UDI fell-short (or UDI-f). The illuminance is greater than 100 lux and less than 300 lux, i.e. UDI supplementary (or UDI-s). The illuminance is greater than 300 lux and less than 3000 lux, i.e. UDI autonomous (or UDI-a). The illuminance is greater than 3000 lux, i.e. UDI exceeded (or UDI-e). The UDI schema was one of the metrics used in a recent, wideranging evaluation of daylight provision for residential buildings (Mardaljevic et al., 2011). Can daylighting be adequately described by a single daylight metric? The question posed above cannot be answered definitively since daylighting is not a well defined property. Notions as to what constitutes adequate in this regard are similarly vague also. Although an ill-defined term, there is probably general acceptance that a space with good daylighting is one that minimises visual discomfort and provides high levels of visual quality under solely or predominantly daylight conditions frequently throughout the year. Thus good daylighting is some aggregate measure over the year of the degree and frequency of occurrence of instantaneous conditions that are deemed to offer good visual comfort and quality. Eventually, many inputs may be combined into one composite performance metric. In the meantime, studying separate dimensions of the daylit environment independently is likely to be more informative. Daylight and architectural pedagogy Most architecture students will have been taught the daylight factor method at some point in their studies. The daylight factor is likely to be the only quantitative measure of daylight performance that the students encounter. A question rarely asked is: what do the students actually learn about daylight performance from the daylight factor? Hands-on use of the daylight factor method is certainly useful to engage students with the issues and problems encountered when trying to evaluate the daylighting performance of a design. However, if the DF method is not taught critically, then the student may complete her studies not appreciating that the DF is an indicator or proxy for daylight performance rather than an actual measure of it. The following sections describe suggestions for a hypothetical curriculum for teaching daylight to architecture students. It is speculative and incomplete, and therefore not intended to be a model for any actual curriculum. Instead, its purpose is to engender wider debate amongst interested parties: teachers, practitioners, researchers and the students themselves. Daylighting basics The first steps in teaching daylighting should be to impart a qualitative understanding of the spatio-temporal dynamics of daylight in a space, and how these are determined by the building form and the available illumination. Whilst this might appear a somewhat challenging task, it is in fact rather straightforward. The simple shoe-box model is ideally suited for this purpose. Fitted with a door security (or peep-hole ) viewer, the student can rapidly experience changes in daylight illumination that, in an actual room, happen too slowly to give a tactile feel for the dynamics of illumination. In addition to obvious relations between say geometry and patterns of direct solar ingress, much more subtle interplays of reflected light within the space can be perceived. In the shoe-box model a window is merely a hole in the sides or the top. However, if the holes are left with a connecting hinge, then the windows can be opened and closed at will by the user who will immediately see the effect on daylight patterns of various multiple apertures. Similarly, a piece of thin tissue paper can be placed over a hole to reveal the effect of replacing clear glass (i.e. a hole ) with a diffusing material. The same can be done with innovative glazings (e.g. prismatic films) provided that any repeating structure is not too large compared to the size of the aperture, Figure 8. 87

90 The key word here is tactile shoe-box studies provide the observer with a genuine feel for the complex relation between the resulting patterns of illumination and the interplay of source, space geometry and the reflective/transmissive properties of the surfaces. In fact, it might be said that the shoe-box model is an illustration of what climate-based modelling is intended to achieve. Models should be kept fairly simple for these studies, with just a few interior surfaces to demonstrate the effect of obstructions, etc. The shoe-box model can be used under almost any lighting condition, though natural light from a window or outside will allow for greater variety and subtlety in experienced illumination conditions than artificial light. If the systematic progression of sun needs to be evaluated, then the shoe-box model could be viewed using light from a heliodon in a similar manner to that used for more carefully prepared scale models, Figure 9. Quantitative measures of daylight Daylight in any quantitative sense should begin with absolute measures such as illumi- nance (lux) or luminance (cd/m 2 ). Students should be given the freedom to relate light meter readings to their own perceptions of a space under a variety of conditions. A number of studies have demonstrated that 300 lux of natural illumination is considered adequate by the majority of building users and also correlates with the notion of a well daylit space. This is something the students could investigate. An excellent exercise in this regard is the study carried out by Reinhart and Weissman: The daylit area Correlating architectural student assessments with current and emerging daylight availability metrics (Reinhart and Weissman, 2012). Scene luminance was until recently a more difficult quantity to measure, and therefore also more challenging to appreciate in a hands on sense. Luminance meters are still fairly expensive, and, of course, give a luminance reading for only a tiny portion of the scene meters typically have an acceptance angle of 1 o or less. A recent technology called high dynamic range (HDR) imaging has greatly expanded our capacity to measure and describe the visual field. A high dynamic range (HDR) image is one where every pixel contains a luminance reading for that point in the recorded scene, in other words: a measurement of luminance, Figure 10. There are a small number of specialist HDR cameras on the market, however it is possible to create HDR images from multiple exposures taken by consumer digital cameras which can have up to 10 million or more pixels (Reinhard et al., 2005). Furthermore, the consumer cameras can be fitted with a full fish-eye lens so the recorded image will be equivalent to or exceed the human field of view. HDR imaging can also be used to measure the luminous flux through building apertures such as windows, facade systems, light-pipes etc. using a simple technique whereby the luminance values in the HDR image serve as a proxy measurement for incident il- luminance (Mardaljevic et al., 2009b). The approach allows rapid quantification of the luminous flux in light-fields of arbitrary complexity where the standard measurement practices would be either time-consuming or impossible to apply with any certainty due to the practical difficulties of carrying out numerous spot measurements covering large areas under natural (i.e. non-steady) conditions. Put simply, a sheet of diffusing material is placed over a building aperture and the distribution of luminance across the diffusing material is measured using a HDR image. If the relation between incident illuminance and the resulting luminance of the diffusing material is known, then it is a straightforward matter to determine the luminous output of the window from the HDR image. Ordinary printing paper can be used for the diffusing material, and the skills required to carry out the measurements are fairly modest and could be made simple enough for non-experts to use in under-graduate laboratory practicals. Thus students could begin to gain an appreciation of windows as dynamic daylight luminaires, allowing into the space a measurable amount of light depending on the external conditions. Such activities will complement the developments in daylight simulation and evaluation where the move is towards absolute measures of illumination under realistic sky conditions. The standard evaluation methods The basis of most guidelines and recommendation is still the daylight factor (DF). Stu- dents should of course be familiar with the daylight factor, but the teaching should strive to make the distinction between the good daylighting and what the daylight factor can tell us. Following on from that, the students should be made aware of the dangers of compliance chasing, and also taught to think critically about received wisdom. Rule-of-thumb methods should not be overlooked since these can help with an appreciation of the basics of daylighting design (Reinhart and LoVerso, 2010). Students should be encouraged to relate DF values to the likely occurrence of internal daylight levels using the long-overlooked method described in a the 1970 CIE document Daylight (Commission Internationale de l Eclairage, 1970). Recently discussed on an EU standardisation panel was a proposal to move the basis of daylight evaluation from relative values based on a single sky (i.e. the DF), to the annual occurrence of an absolute value for illuminance (e.g. 300 lux) estimated from the cumulative availability of diffuse illuminance as determined from standardised climate files. This proposal offers several advantages. 88

91 NORDIC LIGHT & COLOUR Firstly, since the estimate is derived from daylight factors, it requires only a modest enhancement to existing software tools that predict DFs. Next, it provides some connectivity to the prevailing climate. A target that has been proposed is that a side-lit design should achieve 300 lux across half of the work plane for half of the year when the sun is above the horizon. To achieve this for say, Stockholm, half of the sensor points must have a DF of 2.5% or greater, whereas for the Madrid the target DF would be 1.8%. Note, the target is based on the same criterion for internal daylight provision, it is of course the greater prevailing diffuse illuminance for Madrid compared to Stockholm that results in the lower target daylight factor for the Spanish capital. There are other advantages a median approach informs on the spatial distribution of daylight whereas, as noted earlier, the average daylight factor value does not (Mardaljevic and Christoffersen, 2013). Artificial skies An artificial sky provides a controlled means of illuminating a scale model for the purpose of taking measurements and also for qualitative appraisal (Hopkinson, 1963). The most common artificial sky is the mirror box design. This has a horizontal sheet of white diffusing material forming the top of the box. The sheet is evenly lit from behind (i.e. from above) by lamps. The four (or more) vertical sides of the box are mirrors. These create a sky vault that extends seemingly to infinity on all sides due to multiple reflections between the mirrors. Measurements have shown that the luminance pattern in mirror box skies can approximate that of the CIE overcast sky, and so these can provide a controlled luminous environment for the determination of daylight factors. Many of the larger schools of architecture had artificial skies at one time or another, but they tend to be less used since the computer-based methods became more common. Before carrying out any high precision scale model studies in an artificial sky, the user should question what the goal is, and also if it justifies the effort involved. The user learns many skills in constructing the models and carrying out systematic measurements, and the value of that should not be overlooked. However, we know from the work of Cannon-Brookes and others that absolute accuracy of even the most carefully constructed models can be much less than is generally assumed (Cannon-Brookes, 1997). Students should be made aware of these limitations and not strive to achieve an accuracy that may indeed be illusory. Considerable capital investment has been made in the construction and operation of full-hemisphere sky simulator domes for the evaluation of daylight in physical models. As far as the author is aware, full-hemisphere domes cannot reproduce absolute illumination values. Nor can the the illumination effect of the sun be modelled simultaneously with that of the sky, at least not without reducing the absolute illumination from the sky lamps to minuscule levels to maintain the correct relative level with that from the sun lamp. I suspect that most of us would struggle to notice the difference in visual appearance between a model illuminated by a full-hemisphere sky simulator and the same model under an improvised sky comprised of some thin cloth and a few lamps. In consequence, the author remains skeptical that viewing a model illuminated by a sky simulator dome can offer any meaningful insight. Indeed, the perceived benefits of model viewing under seemingly controlled conditions are, I believe, largely illusory, and if it must be done, then it may as well be under a real sky with a real sun. Furthermore, because of the limitations regarding absolute levels, one practice occasionally seen is a designer viewing a model under a clear sky distribution without sun. This is of course an illumination condition that cannot occur in nature and the value of using this approach must be questioned. Climate-based daylight modelling The accurate prediction of daylight in spaces under realistic sun and sky conditions, and for many instances e.g. hourly for a full year, was first demonstrated in the late 1990s (Mardaljevic, 2000)(Reinhart and Herkel, 2000). Climate-based daylight modelling (CBDM) is over a decade old and has been used effectively on a number of projects large and small, e.g. from the New York Times Building to residential dwellings. CBDM tools are however still largely the preserve of lighting simulation experts and researchers. For CBDM to become mainstream the software to do it needs to be taken up and supported by one or more major software houses. Here lies a classic chicken and egg conundrum. On one hand, those who draft guidelines are reluctant to recommend metrics founded on CBDM because tools to predict the metrics are generally not available, at least not as software supported by one of the major vendors. On the other hand, the software vendors are understandably loathe to dedicate the resources to develop and maintain CBDM tools because inasmuch as climate-based metrics are not in the guidelines there will be no real market for these new tools. This presents something of an impasse to all those who strive to advance daylighting standards beyond the current guidelines. Furthermore there is the risk of a skills gap developing in daylight modelling between a small core of CBDM experts and the rest who see little prospect for developing those expert skills inhouse. In other words, there is a risk that the head (i.e. those with CBDM skills) could separate from the tail (i.e. those without CBDM skills), leading to fragmentation in the practitioner user base and barriers to knowledge transfer. 89

92 UDI supp: 100 < E < 300 lux UDI auto: 300 < E < 3000 lux UDI-s UDI-a hrs Area wght. 620 UDI fell-short: E < 100 lux Area wght UDI exceeded: E > 3000 lux UDI-f UDI-e ngham Area wght. 403 Area wght. 26 Figure 11: UDI example (courtesy A + G Architects, Loughborough, UK) 90