<graphics> cyan, magenta, yellow, key.
A system for describing colours by giving the quantity of each secondary colour (cyan, magenta, yellow), along with the "key" (black). The CMYK system is used for printing. For mixing of pigments, it is better to use the secondary colours, since they mix subtractively instead of additively. The secondary colours of light are cyan, magenta and yellow, which correspond to the primary colours of pigment (blue, red and yellow). In addition, although black could be obtained by mixing these three in equal proportions, in four-colour printing it always has its own ink. This gives the CMYK model. The K stands for "Key' or 'blacK,' so as not to cause confusion with the B in RGB.
Alternative systems are RGB and HSV.
(22 Dec 1994)