1. A color difference display method comprising the steps of: inputting data associated with spectral reflectances of respective patches on first and second measurement charts which record a plurality of patches; calculating a hue difference between corresponding patches at identical positions on the first and second measurement charts based on the data input in the inputting step; specifying a color determined by the hue difference calculated in the calculating step; and displaying, for each patch, the hue difference calculated in the calculating step based on the color specified in the specifying step.