I got an answer which seems to work. When converting from XYZ to xy, these distinctions among XYZs don't impact the result. - J Jeff Nova Chief Executive Officer Colorhythm https://colorhythm.com Mobile: +1 510-710-9590 Main: +1 415-399-9921 On Thu, Oct 6, 2022 at 7:50 PM Jeff Nova <jnova@colorhythm.com> wrote:

From the 4.4 spec:

"Un-normalized CIEXYZ values for illuminant (in which Y is in cd/m2)"

"nCIEXYZ values of the illuminant of the PCS, encoded as an XYZNumber"

"nCIEXYZ of media white point."

The ICC defines nCIEXYZ as "CIEXYZ values that have been uniformly scaled so that Y = 1,0 for the adopted white"

I'm trying to convert XYZ to xy chromaticity 1931 diagrams, and it seems the fields I want to show all vary in their flavor of XYZ.

Can anyone point me to any resources that can help us meet these conditions? I'm using the Colour-Science library <https://github.com/colour-science/colour> presently, and their simple *XYZ_to_xy <https://colour.readthedocs.io/en/latest/generated/colour.XYZ_to_xy.html>* function.

Thank you in advance for any help you can provide!

Very best,

Jeff

Jeff Nova Chief Executive Officer

Colorhythm https://colorhythm.com Mobile: +1 510-710-9590 Main: +1 415-399-9921