In short, they first implemented realistic pigment mixing behavior. But in user testing it turned out non-painters are not good at getting the color they want by mixing; you usually end up with brown. So they had to make an unrealistic mixing algorithm that felt more intuitive.
While this work is impressive, two things to consider:
- Mixing oil paints is a learned skill. They don't behave intuitively, so this will only going to be useful for people who already paint in physical media (or want to learn that specifically)
- ArtRage has arguably been the most realistic painting software for over a decade, It has a real color mixing mode that has to be enabled (probably not the default for the aforementioned reasons), and gives much closer results [1] than what they have in the samples page. Yet they barely show it in the comparisons.
Thank you, I knew I’d used real color mixing in multiple apps for years. Secret Weapons is making a categorically false claim to have developed the first ever true-to-life color mixing algorithm.
In short, they first implemented realistic pigment mixing behavior. But in user testing it turned out non-painters are not good at getting the color they want by mixing; you usually end up with brown. So they had to make an unrealistic mixing algorithm that felt more intuitive.