The dots within a screen dithered image look uniform, based on the generalized screen pattern. Banding is a process of reducing colours to 256 or less without dithering. It produces areas of solid colour and results in a posterized effect. Subtractive means that mixing multiple colours creates black. RGB colour is additive, meaning that mixing multiple colours creates white.
Web designers use RGB colours almost exclusively.
RGB CMYK Hexadecimal numbers are used to convert RGB values so HTML can understand which colours have been chosen. For an online facility which will convert RGB values to hexadecimal code, see Color Page Builder . Any image will be forced into a variety of different palettes, depending on which operating system it is viewed with. There are 212 common colours found in the 256-system palettes. Overview For an overview of Internet file formats and related viewers, see Online Electronic Publishing Collection .