An image processing apparatus which decorates color data contained in color image data with different decoration patterns for respective colors of the color data to output the color data includes a determination unit which determines a combination of a color of color data having a highest number of pixels among colors of color data contained in the color image data and a decoration pattern having a lowest number of pixels among the decoration patterns and a monochrome decoration output unit which decorates color data contained in the color image data in accordance with a combination of a color and a decoration pattern corresponding to the color determined by the determination unit for monochrome decoration output of the color image data.