http://www.earlham.edu/~kurtisw/good_slide_show.ppt
http://www.earlham.edu/~kurtisw/rugby.htm
1. What does dithering do? What are the problems with this and how does it relate to the color palette (10 points)
(A) Dithering occurs when two differently colored pixels are placed in such a way to create the appearance of a third color. The drawback of dithering is that the image may become grainy and less sharp (pixilated). The problem with color dithering is associated largely with using the Internet. Computer monitors can usually be set to 256 colors, but browsers only display images at 216 colors. The browser will automatically attempt to compensate for the difference in colors by dithering, but the result will often result in image degradation.
2. Why is GIF the most popular graphics format on the web? (10 points)
(A) The Graphic Interchange Format (GIF) was popularized by the World Wide Web's original designers. Another reason for its widespread use is due to browser compatibility, as GIF images can be read by most browsers. Additionally, they are compressed so that the files size is kept low.
3. What are the advantages and disadvantages of the JPEG format for web graphics? (10 points)
(A) The Joint Photographic Experts Group (JPEG) file format is beneficial because it is 24 bit (true color), compression can be manually adjusted, and is good for images with smooth shapes. JPEG formats are not ideal for images that have hard edges. The more that an image is compressed, the more data it loses and thus decreases in image quality.
4. Color is displayed differently on the screen and by a color printer. How? Why does the computer screen display colours as well as the printer? (10 points)
(A) There are a few reasons for color being displayed differently on the monitor and by color printer. Monitors use transmitted light (RGB) and printers use reflective light (CMYK). Another way that these two methods of display are different is that monitors have around 72-96 dots per inch (DPI), whereas printers use approximately 150 DPI. Transmitted light (RGB) has a wider gamut than reflective light (CMYK), and thus the images are more colorful and true to life on monitors. However, printers have better resolution because they have higher DPI.
5. In displaying an image with HTML why use height and width tags? How are colors represented with HTML? What do you need to look out for when using a background color or pattern? (10 points)
(A) HTML tags tell the browser to allocate a certain amount of space for a graphic. In HTML, colors are represented by hexadecimal codes, such as #000000. Background colors should be use light (as opposed to dark) colors. As with patterns, background colors should be contrasted enough to make the text legible. JPEGs and GIFs are preferable so that the page doesn’t take too long to download.
http://www.earlham.edu/~kurtisw/enhanced.htm
http://www.earlham.edu/~kurtisw/gallery.htm