1. A method of adapting a marking engine comprising: measuring light reflected from an unpatterned target substrate to thereby obtain a target spectrum comprising measurements of the reflectivity of the target substrate at a plurality of different wavelengths; retrieving substrate classification data for a plurality of substrate types from a first storage device wherein the substrate classification data comprises a plurality of representative spectrums wherein each representative spectrum comprises representations of the reflectivity of a known substrate at a plurality of different wavelengths; determining a substrate type for the target substrate by comparing the target spectrum to each of the representative spectrums; retrieving from a second storage device a predetermined color table that is associated with the substrate type; and printing onto target media of the same substrate type as the target substrate wherein the printing is adjusted in conformance with the predetermined color table.