An article on Hackaday I read: "Digital Paint Mixing Has Been Greatly Improved With 1930s Math"

[Zoldyako]

I believe this topic has already been discoursed in the forum:

I realized the spectral mixing of mypaint in krita

[1] [2] I added two new blending modes, over spectral and copy spectral. When krita’s smear brush uses the new algorithm, it can use spectral blending, and mypaint brush is also modified to use spectral blending. This is the modified part of the code, based on krita5 beta 5： https://invent.kde.org/killy/krita/-/archive/master/krita-master.zip