CMYK (short for cyan, magenta, yellow, black, is a subtractive color model, used in color printing.
In additive color models such as RGB, white is the “additive” combination of all primary colored lights, while black is the absence of light.
In the CMYK model, it is just the opposite: white is the natural color of the paper or other background, while black results from a full combination of colored inks.
I applied both the additive and the subtractive combinations by assembling a cyan picnic plate to a magenta and a yellow acetate files. Just to check. And it’s all TRUE!