CMYK is a color model used in printing processes. CMYK is an abbreviation that stands for Cyan, Magenta, Yellow, and Key (black). These colors can be mixed together to create a wide range of different colors. In printing, CMYK refers to the process of using solid particles (usually ink or toner) from a printing machine to create colors on a piece of paper. This allows the printing machine to create a large number of colors on the paper.