When designing web sites, it is important to keep in mind that not all colors look the same on all platforms or in all browsers. In general, colors look darker in Netscape than in Internet Explorer. Also, some colors vary greatly depending on whether they are displayed on a Mac or a PC. Finally, the quality of the graphics card and monitor will affect the display of colors. All of these variations make designing a completely "cross-browser" web site extremely difficult.

While there isn't much to be done about some of the variances in colors across various systems, there is a way to control some of the differences. When developing web sites, there are literally thousands of colors to be used. These are generated from a combination of red, blue, and green. However, if these colors are displayed on different browsers on the same system, the colors may appear different. This had driven more than a few novice designers to distraction. The key is understanding how colors are displayed within browsers.

Graphical web browsers utilize a pallette of 256 colors, which were selected based on a mathematical formula and not by any artistic convention. Any color outside of those colors is dithered (a solid color that the browser cannot display because of palette limitations is replaced with a similar color or a series of lighter or darker dots). In addition, Macs and PCs display 40 of those colors differently. By eliminating those colors, the Web Safe Color pallette was born. The following table defines the remaining 216 colors.