colour mapping

Definition: Procedure of allocating a given hue or colour from an wide or unlimited range of colours to a limited range of colours such as a colour look-up table. * This is the basic processing step when images are converted from their palette of millions or thousands of colours into the limited GIF palette.
Smart matching
The trick is in knowing what to do with a colour that lies midway between two colours in the look-up table: the wrong choice can cause artefacts to appear, with a sudden jump in hue in an otherwise gradual transition. Smart colour mappping adjusts the mapping according the hue of neighbouring pixels. This is different from the problem of rendering intent, where out-of-gamut colours need to be brought into gamut.

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