Abstract: A method is provided for processing digital multi-colour images for the reproduction thereof on a colour printing and/or copying system provided with a plurality of process colours defining a gamut. According to this method the gamut is divided into multiple non-overlapping sub-gamuts, each defined by three chromatic process colours. For each pixel of the digital multi-colour image, a single corresponding sub-gamut is selected based on lightness differences between the respective chromatic process colours.

Abstract: A system and method are provided for processing digital multi-colour images for the reproduction thereof on a colour printing and/or copying device provided with a plurality of process colours defining a gamut. The system includes a colour processing module, which divides the gamut into multiple sub-gamuts, each defined by three chromatic process colours, and which selects for each pixel of the digital multi-colour image the corresponding sub-gamut. For each pixel it is judged whether or not to add a non-white achromatic process colour or blue to the process colours defining the corresponding sub-gamut.