To attain good color reproducibility for a reference color in a printer while quickening the calibration work of the printer.

Control operation is performed to print a color correction patch (standard image) P3 onto the print sheet (print medium) of an objective printer with a standard dot recording rate (ink recording amount). The correction patch P3 printed on the print sheet in an Lab color space (predetermined color space) having a plurality of color components L, a and b is subjected to colorimetry to acquire colorimetric data of the patch P3 for color correction. The colorimetric data is compared with reference colorimetric data and when dot quantity data (print data) D3-D5 are corrected based on the comparison results, the dot quantity data is corrected for variation in dot recording rate among the plurality of color components L, a and b using the comparison results only of the color component quantity having a largest variation thus compensating for color gap in a printer which printed the color correction patch P3.