Patent ID: 7667881

Claim:
A method of copying an original color image, comprising: reading the original color image to generate color image data; converting the color image data into coordinate data including values associated with a first coordinate value and a second coordinate value in a color space, the first coordinate value being indicative of brightness; acquiring correction data including values corresponding to the second coordinate value which are determined in accordance with the values included in the coordinate data and associated with the first coordinate value; correcting the coordinate data with the correction data; printing a color image with the corrected coordinate data, thereby obtaining a copied image of the original color image; printing a reference image with color image data stored in advance; reading the reference image to generate reference image data; printing a copied image of the reference image with the reference image data; reading the copied image of the reference image to generate copied reference image data; converting the reference image data into first coordinate data including first values associated with the first coordinate value and the second coordinate value; converting the copied reference image data into second coordinate data including second values associated with the first coordinate value and the second coordinate value; comparing the reference image data and the copied reference image data to identify deviations between the first values associated with the second coordinate value and the second values associated with the second coordinate value under a condition that the first values associated with the first coordinate value and the second values associated with the second coordinate value have the same values; and determining the correction data based on the deviations, wherein the reference image is an achromatic image.