a nest of bees in graphic design

The InDesign Swatches panel includes four undeletable swatches: None, Black, Paper, and Registration. The purpose of the first three is obvious. You probably know not to use Registration for any object to appear on the printed page, but do you know why?

The Registration color prints on every ink plate. In CMYK, that means anything with Registration applied to it prints in cyan, magenta, yellow, and black. The result is usually not a nice rich black but rather the color of old mud. That’s why the Registration swatch should be reserved for registration marks and other information or structures that need to print on all plates (usually in the slug area), such as the client name, job number, and other specific information. The easiest way to include that information on the film is to set it in the slug area, in the Registration color swatch.