1. A method for processing image data, comprising: generating color image data from a scanned image, the color image data including RGB data; converting the RGB data to CMY data; translating the CMY data for the pixel to CMYK data; setting a weighting coefficient for a pixel based on the values of the CMY data for the pixel; identifying a particular region in which the pixel is located as a black color region or a non-black color region; and altering the value of the K data for the pixel based on the weighting coefficient if the particular region is a non-black color region.