A multipass printing apparatus is characterized by a computer-implemented
controller that controls printing operation so that, on any given pass,
the number of selected print locations onto which printing ink is
deposited by each of N nozzles varies from nozzle to nozzle. The
variation is governed in accordance with a weighted smoothing spline
function, particularly a polynomial B-spline function of the order "j",
where j is a value equal to one less than the number of passes.