摘要:
An apparatus includes a gray converter (220) to convert an inputted color image to be printed into a gray conversion image and to outputs the gray conversion image a difference calculator (230) to calculate a at least one difference value between a at least one color channel image with respect to the color image and the gray conversion image; and a gray reviser (240) to revise the gray conversion image based on the at least one difference value and to output a gray conversion image.