Why Use Duotones?

Duotones are a source of disagreement in the printing industry. Some press professionals call them a waste of two- color press time. Others claim they can turn otherwise lackluster halftones into subtle works of art. Duotones, and their siblings Tritones and Quadtones, print grayscale images by using two (or three or four) separate inks. Usually the inks are colored, but occasionally you ll see a Duotone created by using two black plates. Proponents claim that two blacks can attain a richness and depth out of reach of the simple halftone; critics say it s just one black plate too many. They might never reach an agreement.

No such controversy exists over the use of spot colors. Pressroom shelves are lined with tubs of premixed and mixable inks, and now with six- and eight-color presses becoming more and more common, combinations of four-color process, spot colors, and/or varnishes are being used with greater frequency. Photoshop s spot color channels provide a tool for creating and separating spot colors for printing.

Duotones and spot color differ from process color. Process color produces a complete color and tonal range by mixing cyan, magenta , yellow, and black ink in varying densities , while Duotones and spot color involve printing specific premixed ink colors on a substrate. Even though Photoshop deals with them in different ways, they appear together in this chapter and in the following Hands On project. You ll have a chance to try them out, and then you can decide for yourself where you come down on the Duotone question.