The number of color patches is reduced to attain high-precision color estimation. Hence, the colorimetric values of a plurality of color patches of at least one primary color output by an output device are input. Based on the colorimetric value of first color patches corresponding to a part of the plurality of color patches, colorimetric values corresponding to second color patches other than the first color patches of the plurality of color patches are estimated. Errors between the input colorimetric values of the second color patches and the estimated colorimetric values corresponding to the second color patches are calculated. A plurality of color patches corresponding to the output device is determined based on the calculated errors.