Preferably, test-patterns print on separate, multiple print-medium cards, each including a ramp with colors graded along a certain direction—and, superimposed on the ramp, a candidate add-on colorant. Ramps preferably are printed in so-called “customer colors”, common in snapshots and particularly snapshot regions that include
sky. Positions or amounts of the candidate add-on colorant canvass a likely range of values that optimize camouflaging or suppression of a
banding artifact (due to seams in the pagewide array) that is extended along the same certain direction. For each seam and each “customer color” used, an operator holds up several cards for comparison, selecting the best one to three. Operators thus can evaluate candidate colorant patterns in context of many different tones of the
sky and other customer colors. Preferably banding suppression is integrated with
linearization: at each seam a series of
linearization tables is smoothly interpolated between measurement-based tables for adjacent inkjet dice.