Many printed products, especially in packaging applications, receive a coating with film or varnish, which changes contrast but also hue. Current offset printing standards define only the printing process, but not surface finishing. Standards-based color proofs simulate the uncoated print, but fail to show the final appearance.One approach is to create ICC profiles from coated prints, which is a press- and substrate-dependent solution. A better way would be to predict the effect of various coatings on the basis of standard offset data sets.With this goal in mind, this paper examines surface finishing of offset prints with glossy and matte varnishes and OPP films. Sheets were measured before and after coating. Color changes are most prominent for intermediate screen frequencies (120–150 lpi).A simple model describes the effects of both glossy and matte coatings. Its components are additional dot gain and added stray light for matte surfaces. Measured data before coating were transformed in order to predict the effect of a coating. From this simulation, ICC profiles were created and compared with profiles made from data after coating. For both glossy and matte film, we found an average of 1.5 ΔE₉₄.This model is not limited to a CMYK process, but can be applied to any colorant combination. It is hoped that these findings can be a starting point for work on a standard for coating offset prints, and for other printing processes.