Production of a color conversion profile utilizing comparison of spectral reflectance data and comparative colors

A method of producing a profile defining correspondence between colorimetric value data and ink amount data representing a set of ink amounts of plural inks usable by a printer, comprising the steps of:

• (a) providing a spectral printing model converter configured to convert ink amount data to spectral reflectance of a color patch to be printed according to the ink amount data;
• (b) providing a plurality of sample ink amount data each representing a set of ink amounts of plural inks;
• (c) converting each sample ink amount data into spectral reflectance of a virtual sample patch to be printed with the ink amounts represented by the sample ink amount data using the spectral printing model converter;
• (d) calculating an evaluation index for each sample ink amount data, the evaluation index including a color difference index representing a color difference between a sample color which is calculated from the spectral reflectance and a comparative color which is selected as a basis for comparison;
• (e) selecting plural sample ink amount data based on the evaluation index;
• and
• (f) producing a profile defining correspondence between colorimetric value data and ink amount data based on the selected plural sample ink amount data,
• wherein the step (d) includes the steps of:
• calculating a first colorimetric value of the virtual sample color patch under a first viewing condition as a colorimetric value of the sample color;
• calculating a second colorimetric value of the virtual sample color patch under a second viewing condition as a colorimetric value of the comparative color;
• and
• calculating the color difference index from the first and second colorimetric values, and
• wherein each of steps (c) through (f) is executed by a profile producing apparatus.