InDesign can trap color documents with its built‑in trapping engine, and can also take advantage of the Adobe In‑RIP Trapping engine available on Adobe PostScript output devices that support Adobe In‑RIP Trapping.

Both trapping engines calculate adjustments to the edges of both type and graphics. They apply trapping techniques to different parts of a single object, even if text or an InDesign object overlaps several different background colors. Trapping adjustments are made automatically, and you can define trap presets to address the requirements of specific page ranges. You only see the effects of trapping on color separations generated by a trapping engine; you cannot see the results on‑screen within InDesign.

The trapping engine detects contrasting color edges, and then creates traps based on the neutral densities (lightness or darkness) of abutting colors, in most cases by spreading lighter colors into adjacent darker colors. The trapping settings you specify in the Trap Presets panel modify the trapping engine’s results.