In case of different test and reference illuminants with equal illuminance, the tristimulus values of the corresponding colour in the reference field are determined by giving the tristimulus values of the test sample in the test field. In case of equal test and reference illuminants with different illuminance, the tristimulus values of the corresponding colour in the reference field are determined by giving the tristimulus values of the test sample in the test field. In the case of different test and reference illuminants with different illuminance, the tristimulus values of the corresponding colour in the reference field are determined by giving the tristimulus values of the test sample in the test field. The next step is to select a test illuminant. In the latter case the chromaticity coordinates of the test illuminant have to be keyed in manually.
Decimal point has to bused.
The next step is to select the reference illuminant. CIE Standard Illuminant A, C, D50, D55, D65 and D75.