Some monitors are limited to a palette of 256 colors. If a browser needs to
display a Web page containing a color that is outside of the monitor's palette, the
browser attempts to display the color using dithering. In the dithering process,
alternating pixels of similar colors approximate the original color's appearance. Dithering
can cause images to appear with jagged edges and fuzzy colors.
The safety palette is a collection of 216 colors that are guaranteed to be displayed
without dithering. The palette limits the red, green, and blue components to
the values: 0, 51, 102, 153, 204, and 255. Thus a color value like (204, 51, 153) would be
part of the safety palette, but (192, 124, 255) would not. The tables below show all of the
colors of the safety palette along with the values of their red, green, and blue components.
Note that the safety palette is only required for monitors set at a 256-color resolution. A
monitor with a higher color resolution will not have to employ dithering to display colors
outside of the safety palette.