[julianwa]

Kubelka-Munk is fantastic for modeling the behavior of real world pigments as they're applied in thin layers on a canvas. However, since we were not trying to simulate the act of using physical watercolor, oil paints, etc., it was not only overkill but actually produced unintuitive results.

Our problem is more abstract. We want to appeal to the user's notions of how pigments blend together, but in such a way that the operation is predictable and can be hand tuned to avoid unpleasant cases. Ultimately, the mixing behavior that we released is inspired by the physical world, but is tuned by our designers to produce what they consider pleasing results.