The Netscape Palette

Whilst most computer monitors can display any one of 16,777,216 colours, created from Red, Green and Blue values between 0 and 255, the limitations of most display cards mean that only 256 colours are displayed on screen at once. So, even if you go to all the trouble of creating a high-colour image, it will only be displayed using 256 of the available 16 million colours.

Unfortunately, the limitations do not stop there. Netscape Navigator browsers reduce this palette to 216 colours (6*6*6), produced from just six shades of red, green and blue. If you try to display an image which contains a colour not specified in the Netscape palette, the browser either picks the closest colour or mixes two together (dithering) for use in your image. For this reason, it is sensible when creating icons or other simple images (buttons, menu bars, etc) to use only these 216 colours.

The six values for the colour shades are 0, 51, 102, 153, 204 and 255 (decimal) or 00, 33, 66, 99, CC and FF (hexadecimal). The 216 colours which make up the Netscape palette are shown in the table below.