Glossary » web-safe color palette
web-safe color palette
a set of 216 colors which display correctly on 8-bit monitors for both Macintosh and Windows machines. Each platform has an 8-bit color palette of 256 colors, but they only overlap for 216 of those colors. When colors that are not in the web-safe color palette are displayed on 8-bit monitors, they will usually dither, creating a pattern of color which closely approximates the intended color, but doesn’t match it exactly.
However, with some browsers, a non-web-safe color may be displayed by replacing the color by the closest matching color instead of dithering, or sometimes by displaying a faulty color. Some browsers do not use the standard 8-bit color palette, but instead choose a “best-fitting” color palette to display all the colors on a web page, which can defeat the use of web-safe colors.
The web-safe palette is only important for display on machines that have 8-bit color. The vast majority of machines today have more color, and so are not sensitive to the choice of color palette. Thus, design for this limited palette is not as critical as in the early days of the Web.