Colour palette
<graphics, hardware> (colour look-up table, CLUT) A device which converts the
logical colour numbers stored in each
pixel of video memory into
physical colours, normally represented as
RGB triplets, that can be displayed on the
monitor.
The palette is simply a block of fast
RAM which is addressed by the logical colour and whose output is split into the red, green and blue levels which drive the actual display (e.g.
CRT).
The number of entries (logical colours) in the palette is the total number of colours which can appear on screen simultaneously.
The width of each entry determines the number of colours which the palette can be set to produce.
A common example would be a palette of 256 colours (i.e. addressed by eight-bit pixel values) where each colour can be chosen from a total of 16.7 million colours (i.e. eight bits output for each of red, green and blue).
Changes to the palette affect the whole screen at once and can be used to produce special effects which would be much slower to produce by updating pixels.
