A coloring material color separating section 101 separates an input image into ink colors of a printer referring to an LUT which is registered in the printer as initial values and used for color separation of coloring materials. A total coloring material amount calculating section 102 calculates total amounts of coloring materials equal to amounts of component coloring materials to be used of each pixel from the data passing through the ink color separation, and obtains the maximum value of them. A total coloring material amount adjusting section 103 readjusts the total amounts of the coloring materials of all the pixels such that they become equal to the maximum amount of the coloring materials using the total amount of the coloring materials of the pixel at which the total amount of the coloring material becomes maximum.