I dunno, I found it really hard to mix colours, as everything overpowered the bottom layer. Mixing ultramarine and burnt sienna, did not get me black. Just ultramarine alongside burnt sienna.
Is there any implementation out there that attempts to model the mixture of different color pigments?
It would be cool if we could select a color like "cadmium red" and mix it "titanium white" to mimic a real painting and its interactions, instead of simply select colors in a sRGB space.