FIG. 2 an overall configuration diagram of a printing system in a first embodiment of the present invention. This printing system is composed of: a print data generation apparatus 100 configured to generate print data by implementing a variety of processes for submitted data such as a PDF file; a plate making apparatus 200 configured to make a printing plate on the basis of the print data; a printing apparatus 300 configured to perform printing using the printing plate made by the plate making apparatus 200; a digital printing apparatus 350 such as an inkjet printer/copier configured to perform printing on the basis of print data that is digital data without using the printing plate; and a colorimeter (for example, a spectral colorimeter) 400 configured to perform colorimetry. The print data generation apparatus 100, the plate making apparatus 200, the digital printing apparatus 350 and the colorimeter 400 are communicably interconnected by a communication line CL.
In the present embodiment, in the print data generation apparatus 100, a spectral reflectances prediction process for predicting spectral reflectances obtained by applying ink of a prediction target color (typically, ink of a spot color) on a base material is performed. In the spectral reflectances prediction process, at least one gradation value is designated as a prediction target gradation value, and prediction values of spectral reflectances of the prediction target gradation value for the prediction target color are obtained.
