When it comes to printing, there are four primary colors: cyan, magenta, yellow and black. These four colors are combined to create the full range of colors on a printed page. The letter K is used to represent black because it is made from all three primary colors: cyan, magenta, and yellow. Also, it is the key color and the key is represented by K.
In the printing process, the letters and images are created by using dots of ink or toner. The dots of ink or toner can be made by different methods like sublimation printer, offset printer, or digital printer.