Rasterization: Where the Term Comes From and What It Does:

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1 Rasterization: Rasterization is the term used to describe the process of converting a vector illustration (simple shapes) to a raster image (points and pixels). This is done in design software in order to relieve an image of all excess information, enable editing, and is done when the image is ready to be exported to a bitmap file. Figure 1 is an example of transforming vector shapes into raster images by pixelating the shapes. Figure 1 Where the Term Comes From and What It Does: The word raster comes from the Latin word rastrum (rake) which is derived from radere (to scrape). Rasterization is like rake because it skims over the virtual surface of an image removing information. It is like scraping all unneeded, complex information to leave only the information that is need for the image to exist. Rasterizing an image leaves the visual resolve or resolution (the image quality and amount of detail). It does this so that the designer may edit the image and export it into a new file type called a bitmap. A bitmap is the final image like the images produced by scanners or digital cameras (Fig. 2). These types of images use pixels (a single point on a raster image, Fig. 3) to create a grid of rectangles and squares that when seen from a distance appear as one solid surface. The root word of rasterization is raster which is defined by Webster s dictionary as: a complete set of television lines appearing at the receiver path as a rectangular path of light on which the image is produced However, this is not what the term means in design terminology.

2 Figure 2 Figure 3 How to Rasterize an Image: To rasterize an image in design software you must: 1. Import the image by selecting place under the file menu. 2. Create a layer to place that image into. 3. Select the image or layer by clicking on it.

3 4. Right click to select rasterize. After this has been done adjustments and editing may be done. Another way to select and edit images in layers in to merge (adjustments apply to multiple layers at the same time) the layers. The difference between rasterizing and merging images is that rasterization can be undone and merging is permanent. Once an image has been merged it is not possible to edit single layers; the entire image will change. Vector VS. Bitmap Images A bitmap, or raster image, uses pixels in horizontal and vertical lines to fill areas of color on the computer screen. When these images are enlarged they lose their shape and jagged edges become visible. A vector image is defined by lines and points on a mathematical grid. The difference is that when a vector bases image is enlarged it does not lose its shape because it is not resolution dependant. Figure 4

4 Date: June 29, 2011 To: Olga Menagarishvili From: April Peterson Subject: Reflection on the technical definition I have reviewed my definition of the term rasterization and applied the rhetorical situation to my definition. I have explained how I considered the rhetorical situation when writing the definition and what techniques I used to translate information to the reader. The readers of my definition will be the people in this class. The subject is the design term rasterization. The purpose is to educate and explain the term to people who are not familiar with it. The context of use will be in the classroom. I formatted the definition to cater to my audience by making headings and a list for scan ability. The readers will be students who are used to skimming information for the most important information and will appreciate a direct and to-the-point definition. I also included images to support the text and for clarity so that my audience will be able to visualize what I have written. In order to define the term I needed to use other terms that the audience may not be familiar with so I used several in text, parenthetical definitions. These explain the other words I used to define the term rasterization. I also made analogies and compared/contrasted the term with concepts that are similar and different from the term. I told my readers what the term is like and what it is not like. I made the analogy that rasterization is like a rake and that it scrapes images. I contrasted the term with another similar term that I defined and told how rasterization is not the same as merging. Thank you for reviewing my definition and please contact me if you have any questions; pete6600@umn.edu.

5 Work Sited "How the Rasterization Process Works, the RasterizerState Object." I Love Shaders. 1 May Web. 28 June < When to Merge and Rasterize Layers. Perf. Me4web. Youtube, 16 Feb Web. 24 June < Koenig, Becky. "Chapter 6." Color Workbook. 3rd ed. Upper Saddle River, NJ: Pearson Prentice Hall, Print. Geddes, and Grosset. "Raster." Webster's Dictionary and Thesaurus: with Color Atlas. 2nd ed. Scotland: Geddes & Grosset, Print.