Description of main controls:

-Preserve Saturation: it is recommended to leave this option marked, except when you look for a strict posterization of the luminosity (to the detriment of the colour).
-Posterize: control the number of levels for the posterization of the luminosity.
-Strength: intensity associated to the posterization of the luminosity.
-Primatize: intensity associated to the posterization of the hue. The posterization of the hue is limited to three levels only.
-Shift: to vary the three basic hues associated to the posterization of the hue.