A novel method of preparing a recipe for the reproduction of a particular color on a coloring material from a number of coloring agents or dyes, which comprises passing white light rays through a number of optical filtering means, controlling filtration characteristics of the filtering means to correspond to spectral distribution characteristics of the dyes, projecting on the coloring material the light rays which have passed through the filtering means to produce a monitoring color thereon, and modulating wavelength and amplitude outputs of the filtering means until the monitoring color simulates the particular color. The method precludes the complicated task of evaluating color affecting factors such as surface texture of the coloring material and eliminates the need for repeated coloring tests.