An example method of setting ink limits for a printing system is described. The method involves printing a first set of color ramps. Each color ramp has test areas which are printed based different Neugebauer Primary Area Coverage (NPac) vectors. A test area for each color ramp is indicated that meets an image quality metric and Neugebauer Primary ink use limits are set based on these test areas. A second set of color ramps, for combinations of the set of available Neugebauer Primaries, is then printed, The test areas for each ramp are defined by monotonically-varying vector element values for one Neugebauer Primary in a combination and the second set of ramps are defined by monotonically-varying vector element values across said ramps for another Neugebauer Primary in the combination. Test areas are then indicated again for the second set of color ramps to set ink use limits for the printing system.