Paint-like compositing based on RYB color model

Many people have been familiar with subtractive color model based on pigment color compositing since their early childhood. However, the RGB color space is not comprehensible for children due to additive color compositing. In the RGB color space, the resulting mixture color is often different from colors viewer expected. CMYK is a well-known subtractive color space, but its three primal colors are not familiar. Kubelka-Munk model (KM model in short) simulates pigment compositing as well as paint-like appearance by physically-based simulation. However, it is difficult to use KM model because of many simulation parameters.