In Step S230, an ICM P3a1 calculates an ink amount set φ capable of reproduction of the same spectral reflectivity R (λ) as a target spectral reflectivity Rt (λ) indicated by a spectral reflectivity data RD. An ECM P3a3 multiplies a weight function w (λ) obtained by adding the color-matching functions x (λ), y (λ), and z (λ) in respective wavelengths, when calculating a mean square error of a difference D (λ) between the target spectral reflectivity Rt (λ) indicated by the spectral reflectivity data RD and an estimation spectral reflectivity Rs (λ) as an evaluation value E (φ). In addition, the ink amount set φ is calculated as an optimum solution for minimizing the evaluation value E (φ).