Color processing apparatus, color processing method and storage medium

A color processing apparatus that calculates, from a spectral image having spectral reflectance information that indicates spectral characteristics of a color of each pixel of the spectral image, output information that indicates an intensity of each of a plurality of color components that an image output apparatus uses for outputting the spectral image, the color processing apparatus comprising:

• an acquisition unit configured to acquire the spectral image;
• a calculation unit configured to calculate, for each of a plurality of light sources, a first colorimetric value that is obtained by measuring a color having a spectral reflectance indicated by each pixel of the spectral image under the light source;
• an input gamut obtaining unit configured to obtain, for each of the plurality of light sources, first gamut information indicating a gamut of the spectral image;
• an output gamut obtaining unit configured to obtain, for each of the plurality of light sources, second gamut information indicating a gamut of the image output apparatus;
• a mapping unit configured to obtain, for each of the plurality of light sources, a second colorimetric value by mapping the first colorimetric value of the light source within the gamut of the image output apparatus based on the first gamut information and the second gamut information of each of the plurality of light sources;
• a color separation unit configured to obtain the output information from a plurality of the second colorimetric values, by determining the output information such that an error between a colorimetric value obtained by measuring a color output by the image output apparatus according to the output information under each of the light sources and the second colorimetric value for the light source is minimized;
• and
• an output unit configured to output the output information.