What is "trapping"?

Trapping is a prepress technique aimed at minimizing the effect of misregistration in full-color printing. Misregistration is the slight misalignment of the color plates, which can leave thin white gaps where two colors meet. Trapping slightly overlaps adjacent colors so those gaps do not show.

• The problem it solves: tiny shifts between CMYK plates on press that reveal the paper underneath.
• How it works: one color is expanded slightly into the neighboring color to create a small overlap.
• Where it matters most: where light and dark colors or text and backgrounds abut.
• Usually automatic: modern RIP and prepress software applies trapping for you.