1. A printing system for printing images with colors formed by overlapped combinations of separately deposited separation colors, each separation color corresponding to a colorant, said printing system calibrated to determine the printed color responsive to a requested color, based on a mapping of device independent colors to printer output colors, and providing trapping to correct misregistration between printer output colors due to imperfect placement of said separation colors, including: calibration data stored in a device memory mapping a set of device independent colors to printer output colors; a trapping processor, using said calibration data to determine device independent colors for said printer colors, and including: a trapping calculation processor, converting said device independent colors to a color space in which equivalent color differences in human color perception are approximately equivalent values, and determining whether to trap, a trap color, and a trapping location for the trapping color; an image modification processor, suitable for altering a received image in accordance with any determinations of said trapping calculation processor.