In such a way as described above, the prediction values of the spectral reflectances of the prediction target gradation value for the prediction target color are obtained. Thus, the spectral reflectances prediction process is ended.
Note that, in the present embodiment, a prediction target color setting step is achieved by Step S100, a first relational equation calculation step is achieved by Step S110, a first prediction step is achieved by Step S120, a difference value calculation step is achieved by Step S130, a reference color selection step is achieved by Step S140, a second relational equation calculation step is achieved by Step S150, and a second prediction step is achieved by Step S160. Moreover, a second relational equation using step is achieved by Step S162, and an interpolation step is achieved by Step S164.
<1.4 Effect>