Here is a test to mix colors in different spaces like RGB RYB CMYK CIELab :
Hip File : color_mixing.hip
you will need this vex lib : color.h
Below, from right to left : RGB mixing, RGB or CMYK in substractive mode, RYB with luminance based on RGB, and CIELAB.
Video : A test made with a color mixing in RYB space, I hope to upload soon the hip file for this effect.