The colors found on images and web pages can look very different when viewed on older computers. The reason for this is that some older computers do not have enough color depth to display all of the colors which can be generated on today's computers and monitors. In the "old days" back in 1996, most computers used 8 bit video cards which limited the number of colors a computer could display to only only 256 colors (2 to the 8th power equals 256). The operating systems on those older computers such as Windows, Mac OS and Unix, handled some of these colors differently. Since older computers don't have the capacity to display the millions of colors available on modern computers, if it has to display a color that's not in it's palette, the browser will try to simulate the color by mixing two or more colors from its usable palette together to give the impression of the desired color.

This process is called dithering. With dithering, colors are simulated by displaying sets of two or more dots with different colors next to each other. For example yellow could be simulated by a pattern of red and green dots placed together. Dithering usually leads to a crosshatch or checkerboard type pattern which appears  on the monitor wherever that color is. Using colors which dither for backgrounds or text colors on web pages can make the resulting pages very difficult to read on some computers. Likewise, displaying drawings and photographs on such a computer leads to dithering and may give very poor results.

A graphics designer named Lynda Weinman published a book in 1996 titled "Designing Web Graphics". In it, she developed a chart of colors called "The Browser-Safe Color Palette". Of the 256 colors which can be displayed on older 8 bit computers, 40 of them are displayed differently depending on which operating system is used. The browser safe color chart displays the other 216 color which all older computers display the same no matter which browser is used. Those colors are also displayed the same on modern computers. The process of dithering is not used on any computer for those colors. Therefore, the browser-safe color chart show the 216 non dithering colors which may be displayed safely on all computers new or old.

In the past, Web designers were taught to use only those 216 colors when designing web pages and web graphics so that their work would be displayed the same on all computers. Today however, according to Lynda Weinman, since the majority of the computers being used have the ability to display all 16+ million colors, web designers are free to use whatever colors they wish.

 However, when designing for peripherals such as PDA's, cell phones, etc, the non dithering colors may be used since many of those devices use 8 bit color.
 

Only eight of the non dithering colors are on the extended HTML color name list. Their hex codes are listed below. You may click on the code to see which color names they correspond to:

000000                0000FF                  00FF00                    00FFFF

FF0000               FF00FF                  FFFF00                   FFFFFF

The remaining 208 non dithering colors need to be named and registered. At the present time, we have not been able to locate a source of "official" names for these colors. Therefore, you may name and register them if you wish. However if another person or entity can prove that they have officially named one of them,  The International Color Name Registry reserves the right to remove your name use theirs instead. Please read the Terms and Conditions before you register your color.

To see all 216 non dithering colors, go to the non dithering color table. Then click on the hex code for each color on the table to see if it has been named. If it hasn't, you may choose a name for it and register it.