A spectral printing model converter is used to convert ink amount data to spectral reflectance of a color patch to be printed according to the ink amount data. A plurality of sample ink amount data each representing a set of ink amounts of plural inks is provided, and each sample ink amount data is converted 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. An evaluation index is calculated for each sample ink amount data, where the evaluation index includes a color difference index and an image quality index of the virtual sample patch to be printed according to the sample ink amount data. The color difference index represents 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. Plural sample ink amount data is then selected based on the evaluation index, and a profile defining correspondence between colorimetric value data and ink amount data is produced based on the selected plural sample ink amount data.