The offset printing uses the CMYK system, the combining of 4 basic colors necessary to process the image into printing, this being performed using the halftoning principle. Thus, the paper surface is partially covered by circles in the four basic colors small and frequent enough for the eye to combine the effects of the white surface with the one covered by circles, creating a unitary image.

It is good to know that from the chromatic's point of view the images are directly influenced by the support type's characteristics (white grades, shinny mate or metal surface, etc). The more absorbent the support is, the more the contrast and lightness of the printed image decrease. The printing is also influenced by the paper's or the cardboard's color.

Except for the classic inks (CMYK and Pantone), there are colors with particular specifications ( pearl, that can be scraped for non-absorbent supports or thermo sensible which react when rubbed to a metal surface), leading to special printings.