Where I can find the exact value of Xn, Yn (the luminance factor for the illuminant or perfect white) and Zn?
Xn, Yn, and Zn are the tristimulus values of the illuminant used in the computation of the XYZ tristimulus values of the sample. They are computed the same way as the sample’s tristimulus values with the exception that reflectance is removed from the equations (equivalent to setting it equal to 1.0 or 100%). Due to the normalization of the tristimulus value equations, Yn is always 100.0. Xn and Zn vary above and below 100 depending on the particular illuminant. For CIE standard illuminants, the XnYnZn values can often be found in tabulations of the illuminant spectra in standard texts such as Berns’ “Principles of Color Technology, 3rd Ed.
