What explains the difference between *colour* and *Wikipedia* CIELUV chromaticity diagram?

[danwahl]

Question

Probably a noob question, but I'm curious why the CIELUV diagram generated by colour (plot_chromaticity_diagram_CIE1976UCS()) seems subtly different from the one on Wikipedia (note the u' coordinate of the reference white point):

[KelSolaar]

Hi @danwahl,

This is a great question to which I have no immediate answer! The whitepoint we use is that of our plotting routines working space:

colour/colour/plotting/common.py

Line 170 in e217731

"colourspace": RGB_COLOURSPACES["sRGB"],

It defaults to sRGB thus the whitepoint is D65.

I overlaid the Wikipedia on top of ours and I suspect that there is a rendering issue:

Cheers,

Thomas