There are four traditional types of printing: relief printing (with which this article is mainly concerned), intaglio, lithography, and screen process printing.
As opposed to normal four-colour process printing, the aim of spectral printing is to eliminate or reduce metamerism either due to illuminant or observer.
In this type of industrial or commercial printing, the technique used to print full-color images, such as color photographs, is referred to as four-color-process or merely process printing.
