Abstract: Patches of black and a mixture of color coloring materials are formed on a recording medium, and the chromaticities of the patches are detected (S11). Black tonality data serving as reference lightnesses corresponding to respective tonality data are acquired from pieces of lightness information contained in the detected chromaticities corresponding to the respective tonalities of the black patches. Pieces of black lightness information are corrected on the basis of the acquired black tonality data and the detection results of the black patches. Chromaticities corresponding to the black tonality data are defined as target chromaticities, and the mixture rates of the color coloring materials are corrected on the basis of the target chromaticities and the chromaticities obtained by detecting the patches using the color coloring materials.