A method of dynamic of gamut control is provided for a display having a multi-spectral (typically multi-color) backlight, and sub-pixels corresponding to the different backlight spectra and at least one common sub-pixel. The display may f be an RGBW display having an RGB backlight. The method includes iteratively calculating the minimum required backlight intensities that will allow all (selected) color points of an image to be represented by the display. The determination for a light source of the backlight is based on determinations of intensities determined for other light sources in a previous iteration.