Colour
<graphics> (US "color") Colours are usually represented as
RGB triples in a
digital image because this corresponds most closely to the electronic signals needed to drive a
CRT.
Several equivalent systems ("colour models") exist, e.g.
HSB.
A colour
image may be stored as three separate images, one for each of red, green, and blue, or each
pixel may encode the colour using separate bit-fields for each colour component, or each pixel may store a logical colour number which is looked up in a hardware
colour palette to find the colour to display.
Printers may use the
CMYK or
Pantone representations of colours as well as RGB.
