Short for Cyan-Magenta-Yellow-Black, and pronounced as separate letters. CMYK is a color model in which all colors are described as a mixture of these four process colors. CMYK is the standard color model used in offset printing for full-color documents. Because such printing uses inks of these four basic colors, it is often called four-color printing.

In contrast, display devices generally use a different color model called RGB, which stands for Red-Green-Blue. One of the most difficult aspects of desktop publishing in color is color matching — properly converting the RGB colors into CMYK colors so that what gets printed looks the same as what appears on the monitor.

Offset printing is a widely used printing technique where the inked image is transferred (or “offset”) from a plate to a rubber blanket, then to the printing surface. When used in combination with the lithographic process, which is based on the repulsion of oil and water, the offset technique employs a flat (planographic) image carrier on which the image to be printed obtains ink from ink rollers, while the non-printing area attracts a film of water, keeping the non-printing areas ink-free.

Advantages of offset printing compared to other printing methods include:

• Consistent high image quality. Offset printing produces sharp and clean images and type more easily than a than letterpress printing because the rubber blanket conforms to the texture of the printing surface.
• The more you print, the less you pay, because most of the price goes into the preparation undergone before the first sheet of paper is printing and ready for distribution. Any additional paper print will only cost the client paper price (and ink), which is very minimal.
• High speed and high volume printing.