<graphics> cyan, magenta, yellow, key.
A colour model
that describes each colour
in terms of the quantity of each secondary colour (cyan, magenta, yellow), and "key" (black) it contains.
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 colour models are RGB