1. A color information processing method comprising: inputting reference data including color information about each pixel or each pixel group of a reference medium and evaluation target data including color information about each pixel or each pixel group of an evaluation medium by an input means; performing an image matching process of image matching the input reference data and evaluation target data by an image processing means such that pixel levels thereof correspond to each other; setting a specific area which is a unit of evaluation and includes a plurality of pixels to each data item subjected to the image matching process by an area setting means; and comparing the color information items about each pixel or each pixel group in the reference data and the evaluation target data in the set specific area to calculate a color difference and performing an averaging process to calculate an average evaluation result for the specific area by a calculation means.