Acrobat can automatically trap color documents with the Adobe In-RIP Trapping engine, which is available on Adobe PostScript output devices that support Adobe In-RIP Trapping.
Adobe In-RIP Trapping can precisely calculate and apply any necessary adjustments to the edges of type and graphics throughout your document. It can apply effective trapping techniques to different parts of a single object, even if the object overlaps several different background colors. Trapping adjustments are made automatically, and you can define trap presets to address the trapping requirements of specific page ranges. The effects of trapping are apparent only on color separations generated by the trapping engine; you cannot see the results on-screen within the program.
The trapping engine decides where to trap by detecting contrasting color edges. It 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 palette modify the trapping engine’s results.
Adobe In-RIP Trapping requires the following software and hardware:
A PPD (PostScript Printer Description) file for a printer that supports Adobe In-RIP Trapping. You must select this PPD by using the operating system driver.
An Adobe PostScript Level 2 or later output device that uses a RIP that supports Adobe In-RIP Trapping. To find out if a PostScript output device supports Adobe In-RIP Trapping, contact the manufacturer or your print service provider.