A number of sets of color values for an imaging system to output a corresponding number of neutral gray outputs at different lightness levels, is computed by interpolation, based at least in part on received or taken measurements of a number of near-neutral patches for the different lightness levels printed by the imaging system using a number of sets of color values of the imaging system's color space. The color values of the imaging system's color space are derived based on a number of sets of color values of a profile connection space (PCS) in accordance with a print table of a color profile of the imaging system mapping color value sets from the PCS to color value sets in the imaging system's color space. The various sets of defining color values define the near-neutral patches in the PCS.