CMYK is a practical application of the CMY colour models in which black is used alongside the three primary colours (cyan, magenta and yellow) to enable digital printers to produce darker and denser tones.
The CMY colour model is a subtractive color model.
CMYK is based on the CMY color model and is the standard model used for colour printing.
CMYK refers to the four ink plates used in some color printing: cyan, magenta, yellow, and ‘key’ (black).
The CMYK model works by applying and overlaying colours that partially or entirely mask the background colour (usually white). The ink reduces the light that would otherwise be reflected.
CMY is called a subtractive colour model because the inks “subtract” the colors red, green and blue from white light.
White light minus red leaves cyan, white light minus green leaves magenta, and white light minus blue leaves yellow. ??