US Patent 7796298 Image processing method, image processing apparatus, and storage medium

In generating a conversion characteristic look-up table between an output device dependence color space and device independence color space, when white and black correction is performed for a colorimetric value of a sample chart output from an output device, the values of the chromaticity components of the white point of the colorimetric value are maintained even after the correction. In addition, the conversion characteristic look-up table is generated such that only a corrected white point is corrected to a reference white point so as to make the reference white point smoothly continue to other grid points.