High quality reproductions made by prepress operators were studied in order to derive gamut mapping strategies. Ektachrome transparencies were reproduced on gloss coated and newsprint hard copy media, and the implicit mapping strategies in dimensions of hue, lightness and chroma were analyzed. The results supported some elements of the CARISMA gamut mapping algorithm, including a shift in hue towards the colorant primaries of the reproduction media and (for gloss coated media only) linear lightness scaling from the minimum and maximum L^* lightness of the image to those of the reproduction media. Compression of lightness and chroma towards the achromatic axis was found to be non-linear, and to have a variable convergence point. A gamut mapping algorithm incorporating these features (Graphic Arts Media Mapping Algorithm or GAMMA) was compared to other mapping methods in a transparency-to-newsprint workflow. The experiment compared different methods of determining the achromatic convergence point in simultaneous lightness-chroma compression, and compared linear compression against a non-linear distance-weighted compression. Non-linear compression methods and variable, lightness and chroma dependent convergence points performed better than those with linear compression and fixed convergence points.