I think so, straight lines within the RYB color wheel though. MyPaint has an RYB wheel (edit-preferences-color-wheel-traditional). I switched to the RYB wheel and created HCY masks to demonstrate how RYB mixing might look. Yes it is muddy, but I started with fairly desaturated colors and I think this is really how it should look if they are pigments. I had to pluck the RYB colors from the mask manually so it is approximately evenly-spaced along the masks. The last HCY row I nudged the values of the yellow and blue a tiny bit so that the hue rotation went “the other way”. So, I don’t really understand anything BUT maybe @AnTi code can be tweaked to somehow just use the RYB wheel’s hue values? Does it make sense to say HCY space with RYB primaries?
