In the present embodiment, in a spectral reflectances prediction process, after a reference color is selected, obtained is a union of gradation values for which spectral reflectances are obtained regarding the reference color and gradation values for which spectral reflectances are obtained regarding a prediction target color. For example, if the gradation values for which the spectral reflectances are obtained regarding the reference color are 0, 0.2, 0.5, 0.8, and 1, and the gradation values for which the spectral reflectances are obtained regarding the prediction target color are 0, 0.3, 0.5, and 1, then the union is 0, 0.2, 0.3, 0.5, 0.8, and 1 (see FIG. 16). For a prediction target gradation value which is included in the union, prediction values of the spectral reflectances are obtained by the second relational equation, and for a prediction target gradation value which is not included in the union, prediction values of the spectral reflectances are obtained by spline interpolation (for example, cubic spline interpolation).

Note that, in the present embodiment, it is assumed that the second relational equation is calculated by a method similar to that in the above-described second embodiment. However, the second relational equation may be calculated by a method similar to that in the above-described first embodiment.

<3.2 Configuration and Spectral Reflectances Prediction Method (Spectral Characteristics Prediction Method)>

An overall configuration of a printing system and a configuration of a print data generation apparatus are similar to those (see FIG. 2 and FIG. 3) of the above-described first embodiment, and accordingly, a description thereof will be omitted.