Lighting Fact Sheet Tungsten light is color balanced at 3200 degrees Kelvin. There are two types of tungsten lights Type A at 3200 degrees Kelvin and Type B at 3400 degrees Kelvin. All modern tungsten lights and films are balanced for Type A tungsten. Tungsten studio lights are often called hot lights because of the heat they produce. Always use oven mitts or similar hand protection while working with studio tungsten lights to prevent burns (you can get second or third degree burns that peel the skin off if you touch the lights while they are hot). Photographic quality tungsten lights use quartz halogen bulbs because they last longer than normal bulbs and they maintain a consistent color temperature (3200 degree Kelvin) for their entire life span. The expected life span of a quartz halogen light is 250 to 300 hours. Mentioning tungsten light automatically infers that it is coming from a continuous light source. The light is either on or it is off. The advantage of a continuous light source is that you can see exactly what you are photographing. In other words, what you see is what you get on the film. The shadows, highlights, light reflection, light refraction and diffusion are visible to the photographer before he/she takes the picture. Tungsten light sources are recommended to everyone when they first start photographic lighting, because they are easy to use. Tungsten film can be shot under daylight conditions (sun, flash or strobe balanced at 5500 degrees Kelvin) if an 85B filter is used. The orange 85B filter will color correct or light balance for the blue/cyan layer that is built into tungsten films. Tungsten films are made for long exposures. Reciprocity is very good for tungsten films and the recommended exposure range is between 1/1000 of a second and a full 32 seconds. Tungsten films are denoted by the use of a T at the end of the film name such as Kodak 64T or Fuji 64T. They may also be denoted with an L at the end of the film name such as Fuji NPL or Kodak VPL. When Polaroid Type 54 (ISO 100) is used in the studio under tungsten lights it should be rated at and ISO of 64. Most B&W films need to be rated lower under tungsten light sources, for example Kodak T-Max 100 should be rated at either ISO 80 or ISO 64 depending on the developer, developer dilution and agitation in your development process.
Tungsten light exposures can be manipulated by shutter speed or aperture on the camera, because it is a continuous light source. Using a longer shutter speed is recommended to maintain your desired depth-of-field. Remember that tungsten films are made for longer exposures. Set your light meter to the ambient light setting (continuous light, or outdoor light) when metering for tungsten light. To manipulate the intensity of the light when using tungsten light sources: 1. Push the light closer to the subject or move the light father away from the subject. 2. Change the light bulb or light source for a more or less powerful light 3. Use a neutral density filter on the camera or neutral density gel on the light 4. Shoot faster or slower speed film 5. If the situation does not call for specular (hard) light, try diffusing the light 6. Add or take away a light or light source (light, reflector, etc.) The parts or components of a tungsten studio light are: 1. Housing 2. Fresnel 3. Mirror (curved) 4. Quartz Halogen Light (balanced at 3200 degrees Kelvin) 5. Slide or Geared Transport Mechanism (that allows the light to be used as a wide flood light or a concentrated spot light) Light attachments that are commonly used with tungsten lights are: 1. Barn Doors 2. Snoot We currently have four brands of tungsten lights: 1. Arri (French) Blue Housings we currently have powers of 300-watt, 650-watt, and 1000-watt or 1K. When we get into watt power ratings of 1000 or over it is typically denoted as 1K for 1000, 2K for 2000, etc. 2. Desisti (Italian) Yellow Housings we have 2000-watt or 2K lights, 1000- watt or 1K lights and 300-watt lights. 3. Mole-Richardson (U.S.) Red Housings we have 1000-watt or 1K lights 4. Tota-Lights (U.S.) in the cage for location check-out only, 600 watt.
Warm light is red, orange, gold and/or yellow light. Cool light is blue and/or green light. In what seems to be exactly backwards for most people warm light is lower in color temperature than cool light. Conversely, cool light has a higher color temperature than warm light. kelvin (K) Measurement unit of color temperature. Named after the scientist Lord Kelvin who discovered how to measure the color temperature of light. Light is judged in three categories: 1. Intensity total amount of light output, how powerful the light is, etc. 2. Quality color temperature, diffused or specular, etc. 3. Direction front light, back light, side light, etc. Origination of the light, where it creates highlights and casts shadows. The main light source is the light with the highest light output. It can be the sun, a high output flash, a large tungsten light or fluorescent overhead lights. Regardless of the light color temperature, the main light is the light source with the highest intensity light output. Fill light is light cast from a secondary light source that fills-in shadows or lightens shadows and reduces scene contrast. The secondary light (fill light) can be a second light, or a reflector (such as a mirror, a white bounce card, or a colored light reflector). Gold is most common color to add warmth and blue is the most common color to add coolness to a person or scene. Inverse Square Law With a point source of light, intensity at a surface is inversely proportional to the square of its distance from the source; e.g. half the original distance is 2 2 or four times the intensity of the light or twice the distance is ¼ the intensity, three times the distance is 3 2 or one-ninth the intensity or one-third the original distance is nine times the intensity. Ambient Light General term covering existing light. Any continuous light not provided by the photographer. Glare a strong, steady, dazzling light or brilliant reflection (specular highlights) Flare a short-lived, spotlike outburst of increased brightness (e.g. sun spots) Reflection the throwing back by a surface of sound, light, heat, etc. (often with consequence); to give back an image or likeness The angle of incidence is the angle of reflection. In other words, light reflects off the subject at the same angle at which it was cast on to the subject. Refraction the bending of a ray of light, heat or sound as it passes obliquely from one medium to another of different density, or of which its speed is different or through layers of different density in the same medium.
Flash and Strobe are daylight balanced at 5500 degrees Kelvin. Daylight film may be shot under tungsten lighting conditions if an 80A filter is used over the camera lens or the light itself. Flash is always metered by f-stop or aperture. The exposure on the subject is controlled by the aperture. The background illumination (how bright or how dark the background) is controlled by the amount of ambient (surrounding) light and the duration of the shutter speed (how long you leave the shutter open). A longer shutter speed will allow the background to be brighter and allow the ambient light to color the scene. With long or slow shutter speeds motion may be prevalent in the image and the subject will be frozen by the flash. A shorter shutter speed will make the background darker. Most notable is on camera flash at night with a 1/60 or 1/125 shutter speed. The subject is lit up and the background is totally dark. Flashes (and/or strobes) store power in a capacitor and release it all at one time creating a fast, high-powered burst of light to illuminate a scene or subject. Flash output is controlled by many variables: watt-seconds (joules), flash tube design, reflector design, cable design (if using a power pack), guide number, etc. The most common of the power variables is watt-seconds. Nearly every flash is measured in watt-seconds, but not every rating scheme is the same. The capacitor in the flash/strobe may be able to produce a said amount of watt-seconds in a laboratory, but when the power is translated through the circuitry, and into final output, (taking into consideration the quality of the capacitor components, the loss of power as it is moved from the capacitor to the flash tube, the flash tube design and the flash tube itself, as well as the reflector design and reflector itself) the intensity of the light and the evenness of the light may not be what the photographer was expecting. Nevertheless, we will consider watt-seconds as a basic valid measurement for flash power and light intensity. Watt-Second or Joule Light output given by one watt burning for one second. Used to quantify and compare the power of output of electronic flash (but ignores the influence of flash head reflector or diffuser on exposure). Capacitor Unit for storing and subsequently releasing a pulse of electricity. Light attachments that are commonly used with flash units are: 1. Reflectors various shapes, sizes, colors and textures 2. Barn Doors to control the overflow of light to the sides 3. Snoot concentrates light into a beam 4. Umbrellas reflective diffuser or shoot through diffuser for softer light 5. Soft Boxes and other diffusers various shapes and sizes, e.g. globes and boxes 6. Grids or Grid Spot Attachments focus light into a concentrated area similar to a snoot, but more compact.
Flash power can be manipulated through the use of resistors, which allow the capacitors to release maximum power (all their power at one time) or lesser power amounts. We typically refer to this as dialing down the power, because the resistor is controlled through an analog dial or a digital switch. There are two major types of flash/strobe units: 1. Monolight all in one units; the flash capacitor, resistor, flash head and flash controls are built into one housing. It is very simple to operate and great for location shooting. Each light has to have access to AC power. 2. Power Pack the power to lights is controlled through a power pack, which typically has more power than a monolight. The power pack itself plugs into the wall and controls the capacitor, resistor and light output controls. The light is separate and plugs into the power pack. A power pack controls two or more lights from a single location and only requires one AC power connection. We have three brands of flash in our studio: 1. ProFoto black casings some are 1200 watt-second monolights that have their controls on the back of the unit and some are lights that connect to our 2400 watt-second ProFoto Acute2 power packs. 2. Bowens ProLite Monolights (750 w/s) and Bowens Espirit Monolights (1500 w/s) The gray housings are the ProLite 100s that produce 750 watt-seconds or power. Their controls are on the back of the unit. The black housings are the Espirit lights that produce 1500 watt-seconds of power and have a six stop adjustable range via controls on the side and back of the unit. 3. Calumet TravelLites brown/black housings the TravelLites are 750 watt-second monolights very similar to the Bowens ProLites (because they are manufactured by Bowens for Calumet). They have controls on both the back and side of the unit. Pocket Wizard radio slaves use radio frequencies to trigger flash sync with the camera. We have Pocket Wizard Transceivers that can be used as transmitters, receivers or relay switches for transmitters. Each transceiver has 32 possible channels (radio frequencies), but the transceivers have to be set to the proper function (transmitter for the camera sync or receiver for the flash sync) and set to the same channel before they will work. If a power pack is asymmetrical then all its outlets, lights and/or light banks can be controlled separately on the pack controls modeling lights included. Each light will have its own power control(s). Symmetrical power packs can be controlled by one single control panel. Symmetrical power packs have two or more light banks. Each light bank may power more than one light, but the controls are for the entire light bank (all the lights in the light bank have their power linked to one control so it is impossible to vary the power output of individual lights).
To increase light intensity (more light) we can: 1. Push the light closer to the subject. 2. If the light allows it, we can increase the power of the light by dialing up the power. 3. Change light sources or power packs to get a more powerful light or power pack. 4. Use a faster speed film with possible grain, tonality or color changes. 5. Use multiple pops from the flash unit. 6. Add a light or a light source such as a reflector. To decrease light intensity (less light) we can: 1. Move the light farther away from the subject. 2. Use neutral density filters on the camera or on the light. 3. Diffuse the light possibly even double diffusion. Remember, diffusion will change the quality of light hitting the subject. 4. If the light allows it, dial down the power of the light. 5. Use a slower speed film with possible grain, tonality or color changes. 6. Change light sources or power packs to get a less powerful light or power pack. 7. Subtract a light or light source such as a reflector Different types of flash heads include: 1. Standard flash head, with or without reflector. 2. Ring Light or Ring Flash a flash that is a ring around the camera lens. 3. Twin Head two flash tubes to generate twice the flash power or light output. 4. Spot Light a focusing spotlight for a concentrated beam of light Daylight film is color balanced at 5500 degrees Kelvin for daylight (flash, strobe and sunlight). It is geared toward shorter exposures (1/10,000 of a second to 1 second). Reciprocity is generally not good for daylight balanced films past one second. However, there is one notable exception, Fuji Provia 100F, that can be exposed up to 128 seconds with no exposure adjustment. Flash can be synced (synchronized) with the camera through the use of three devices: 1. Traditional Sync Cord cord attaches camera to flash unit 2. Infrared (IR) line of sight slaves 3. Radio slaves
Modeling lights for flash units have tungsten light bulbs. Modeling lights are continuous burning lights with a very warm color temperature (2600-3400 degrees Kelvin) meant for focusing and previewing highlights/shadows. They should be shut off before shooting if using an exposure time of longer than 1/60 th of a second. If they are not turned off for longer shutter speeds they could influence the image color. Modeling lights can be placed on several power settings through the use of a resister similar to the flash itself. The most common modeling light settings are full power, dim or proportional. The proportional and dim light settings match the modeling light output setting to the flash power output setting. Lighting Ratios: 1:1 Even light or Flat light 1:2 One-stop between highlight and shadow 1:3 One and a half stops between highlight and shadow 1:4 Two-stops between highlight and shadow 1:6 Two and a half stops between highlight and shadow 1:8 Three-stops between highlight and shadow 1:12 Three and a half stops between highlight and shadow 1:16 Four-stops between highlight and shadow 1:24 Four and a half stops between highlight and shadow 1:32 Five-stops between highlight and shadow Lighting ratios are based on the exponents of two similar to Bellows Extension Factors (BEF) and Multiple Flash Pops. Low Key lighting is referred to as lighting with definite highlights and shadows. The lighting ratios are generally 1:3 or higher. Some people call it mood lighting. High Key lighting is considered to be light from everywhere. The lighting ratios are usually 1:1 or 1:2 including the background. Shadows are filled in with and additional light source or a reflector. Flags are light blocking devices, usually black in color, that prevent light from spilling over into the camera lens or that help prevent light from causing reflections in objects. Gobos are flags of specific shapes that block light to create a shaped shadow in the picture or allow light to pass through to create a shaped highlight in the picture. e.g. words, stars, company logos, etc.
How to change the Quality of Light: 1. Reflectors of different colors, sizes, shapes, etc. 2. Diffusion scrims, umbrellas, soft boxes, etc. 3. Gel the lights physically place gels over the lights to change their color 4. Light shaping devices flash reflectors, snoots, grids, glass blocks, etc. 5. Change light sources physically change the light itself, change the bulb or change the flash tube (newer bulbs are generally more color correct and slightly brighter). 6. Add mixed light add another light source with a different color temperature. Bellows Extension Factor (BEF): Bellows Extension (distance from lens plane to film plane) squared BE 2 divided by Focal Length of Lens squared FL 2 The bellows extension factor (BEF) then must be converted into stops based on the exponents of the number two. 1 no bellows extension 1.5 one-half stop 2 one stop 3 one and one-half stops 4 two stops 5 two and one-third stops 6 two and one-half stops 7 two and two-thirds stops 8 three stops 10 three and one-fourth stops 12 three and one-half stops 14 three and three-fourth stops 16 four stops 20 four and one-quarter stops 24 four and one-half stops 28 four and three-quarter stops 32 five stops 40 five and one-quarter stops 48 five and one-half stops 56 five and three-quarter stops 64 six stops
Parts to a Flash unit: 1. Housing 2. Capacitor 3. Resistor 4. Quartz Flash Tube 5. Tungsten Modeling Light/Lamp 6. Sync (by Cord, Infrared Slave or Radio Slave) 7. Reflector 8. AC Cord or DC power supply 9. Light Stand Mount and Swivel 10. Light Stand Factors that determine depth-of-field: 1. Aperture 2. Magnification Proximity or how close you are to the object you are trying to photograph 3. Focal Length of Lens the length of the lens really does not control depth-of-field, but it is important to understand that shorter focal length lenses focus at infinity much faster than longer focal length lenses. (e.g. a 90mm lens on a view camera is a short or wide angle lens and only takes 90mm of bellows draw to focus at infinity while a 300mm lens on a view camera is considered to be a telephoto lens and will focus at infinity at 300mm of bellows draw). Shorter lenses will always appear to give more depth-of-field because they focus at infinity so quickly. The 90mm lens may reach infinity focus for a subject five feet away and render the entire scene (foreground and background) in focus. It may take and object being 20+ feet from the camera for the 300mm lens to get the entire scene in focus. Two methods of metering light: 1. Incident light is cast directly on the white dome of the meter. The light is automatically averaged for proper exposure. 2. Reflected a spot meter reading is taken by pointing the meter directly at the subject. It then reads the light reflected off the subject (for that spot only) and returns a value of middle gray or Zone V. The photographer then must choose whether to use the reading as is or change it to make the subject lighter or darker.