Trapping is a printing term used to describe the solution to a specific printing problem. This occurs when two or more colored objects overlap and cause misregistration due to the physical problem of lining up of separate plates, not to mention the ink absorption rate of the type of paper used. The solution is to expand or shrink a particular object (also known as “spreading” or “choking”) to compensate for the physical inaccuracies.
To view the default trapping values of the document’s colors select “Show Trap Info” from the Views menu, or press command-T.
The Trap Info dialog will display a list of those colors which have trapping values defined. Click to select a color and the trap specifications for its defined background colors will be listed.