Image processing apparatus and image processing program

A non-transitory computer readable storage medium storing an image processing program, the program for generating data for reproducing a color of a dot image formed by a printer using a first color material, in an image forming apparatus, the program causing a computer to realize:

• a grayscale data generation function of generating input grayscale data in which a grayscale value corresponding to a dot area ratio is stored in a peripheral part of a dot, and a grayscale value corresponding to a color of a dot portion of the dot image is stored in a core part surrounded by the peripheral part, on the basis of dot data indicating the dot image;
• and
• a color conversion function of converting the input grayscale data into output grayscale data indicating a usage amount of a second color material used in the image forming apparatus,
• wherein, in the color conversion function, first color conversion is performed on the grayscale value of the core part, and second color conversion different from the first color conversion is performed on the grayscale value of the peripheral part.