A typical printing press uses 4 colours of ink to create full-colour photographic images. The four inks are placed on the paper in layers of dots that combine to create the illusion of many more colours. CMYK refers to the 4 ink colors used by the printing press. C is cyan, M is magenta, Y is yellow, and K is black. Cyan, Magenta, Yellow and Black are called subtractive colours. Consumer ink-jet printers use CMYK toners in much the same way to produce full-colour printing. Combining them all gives the colour black. When combined in various percentages, these four inks will create an entire spectrum of colours.
The CMYK offset printing method is also known as “four-colour process” or simply “process” colour. All of the colours in the printable portion of the colour spectrum can be achieved by overlapping “tints” of cyan, magenta, yellow and black inks. A tint is a screen of tiny dots appearing as a percentage of a solid color. When various tints of the four colors are printed in overlapping patterns it gives the illusion of continuous tones – like a photograph.