Mixing colors according to the book
It took many iterations, lots of code, lots of mathematics. But in the end, Emanuele Tamponi has succeeded where others have failed miserably: if you use Krita's new paint mixer to mix colors, you will get green from blue and yellow, purple from blue and red and orange from yellow and red.
This is truly an advance of the state of the art. By comparison, the Corel Painter mixer palette degenerates into ugly brown much faster.. Maybe their mixer is still based on simple cmyk addition, as Bill Baxter suspected. Of course, we still need to do work on the wetness-dryness selection UI, add a color picker functionality, a brush clean button and complex blend loading. There's always more to do.
But... Look at that wonderful green!
Oh -- and let's not forget to mention Paolo Capriotti, who helped Emanuele with some of the mathematics.