A scanner profile previously retains process color components (such as CMYK) used for profile generation. Grid points are selected from a scanner profile corresponding to the process color components (CMYK) for any output device value of an input image. An output device value for color patch is acquired while the output device value for color patch results from adding a color (R) except the process color components (CMYK) for any output device value to the CMYK process color components retained at the selected grid points. A color patch (chart image) is generated based on the output device value for color patch.