CMYK, which stands for C=cyan, M=magenta, Y=yellow, and K=key (or black), is the color model used in most printing.
It is also referred to as an abstract color model, and if you don't understand what that means or how it works, the following excellent demonstration will help you understand it.
The video shows how each subsequent color after black and white subtracts luminance from the background to create the final color of the image. In the CMYK, all colors are added together to ultimately create black, compared to the additive RGB model where white is the result of combining R=red, G=green, and B=blue.
In the video you will see 4 glass pieces that if placed one on top of the other, Vermeer’s painting “Girl with a Pearl Earring” emerges in color. The video is of course an advertisement for the sale of these tiles as coasters, but it is still a very good example for those who want to learn about color analysis and digital color imaging.
Watch the video below:
https://www.youtube.com/watch?v=3j4GCRH9w7o
