With such a configuration, the first relational equations which represent the relationships between the spectral characteristics of the maximum gradation values and the spectral characteristics of the characteristics-acquired gradation value (the intermediate gradation value for which the spectral characteristics are obtained regarding the prediction target color) are obtained for each of the sample colors, and using the first relational equations for respective sample colors, the prediction values of the spectral characteristics of the characteristics-acquired gradation value for the prediction target color are obtained. Then, the difference values between the prediction values and the actual measurement values are obtained, and a sample color for which the minimum difference value is obtained is selected as the reference color second relational equation that represents characteristics of the reference color is obtained, and prediction values of spectral characteristics of a prediction target gradation value for the prediction target color is obtained using the second relational equation. As above, the spectral characteristics are predicted for the prediction target color using, as the reference color, the color in which known spectral characteristics for the prediction target color can be predicted with highest accuracy. Accordingly, highly accurate prediction values are obtained. Thus, in a case in which there is an intermediate gradation value for which the spectral characteristics are known regarding the prediction target color, high accuracy prediction of the spectral characteristics of the prediction target gradation values for the prediction target color is enabled using the information on the known spectral characteristics.