Selecting a set of inks for colour process printing

Selecting a set of inks for colour by printing a digitally generated preview of a separated source design as it would appear if printed using a given combination of production process substrate and inks is selected. A target design is also selected and individual areas, which may be pixels or objects, of the preview are compared, area by area, with corresponding areas of the target design. The results of that comparison are evaluated according to user defined criteria including average colour difference, maximum colour difference and ink cost. The comparison process is repeated for further previews in order to determine a set of inks providing a close match to the target design.