TIM - CYMK

CMYK is used in color printing, and is also used to describe the printing process itself. CYMK refers to the four inks used in some color printing:

• C=cyan
• M=magenta
• Y=yellow
• K=key (black)

The reason this is considered a “subtractive color model” is because the higher percentage of cyan, magenta, and yellow you smear onto a white sheet of paper, the less amount of light that will reflect through, ultimately creating a black (in this case, smudge) on paper.
Why is black referred to as the letter “K” in CMYK?  Allegedly, the K actually stands for Key, as in the key plate used by a printer. It was referred to as the key plate because it generally contained the artistic detail for a piece.

The advantage of CYMK or CKYM is that you had a code to follow, its easier for someone to know what colours to use first and to follow a guideline with a good outcome.
The disadvantage of this is it won't work for every image, this is more for a realistic print, and using it for things like patterns may not give out the same outcome as patterns tend to be bolder.