What Is Registration & Trapping In Commercial Printing?

By Author: Dean G
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Registration
Register is the correct positioning or fitting of an image(s), especially when being printed using two or more plates on press. If the plates are not properly aligned the item will appear out of register.

Trapping
Trapping digital files is the process of compensating for misregistration on press by printing small areas of overlapping color where objects meet.

Knockout: In most cases, when two objects of different colors overlap the knockout, meaning they will not print on top of each other. In the first example below, the blue circle knocks out the red box, removing the red ink below the blue circle. Knockouts such as this may require trapping to insure that no unsightly gaps occur due to misregistration.

Overprinting: Overprinting is when one ink color is printed over the top of another ink color. Depending on the colors being, used you will notice varying degrees of color change where the two objects overprint. In the second example below, the yellow circle was printed over the cyan box causing the overlapping areas to appear green.