Method of mapping source colors from a source color device having an actual source gamut that is represented by a source convex (gamut boundary descriptor) and a source non-convex into target colors for a target color device having an actual target gamut that is represented by a a target convex and a target non-convex, comprising,1—if the source color to map is located outside the source non-convex, a pre-mapping step that maps the source color into the source non-convex, 2—if the mapped target color is located outside the target non-convex, a post-mapping step that maps the target color into the target non-convex. This method allows precise gamut mapping while allowing also for simple geometrical operations using convex gamuts.