Abstract: A method for controlling the printing of overlapping swathes, the swathes extending perpendicular to a succession of print lines; for each print line a transition is defined between one swathe and the next, with the location of the transition in the print line varying between print lines, for example varying pseudo-randomly or as a curve extending in the swathe direction.

Abstract: A method for compensating for a tendency for droplets deposited by a plurality of nozzles of an ink jet printer to merge in the direction of printing on a substrate, comprising: identifying lines of pixels to be printed by each nozzle which have a grey level greater than a first threshold value; selecting certain of those pixels which are separated by a distance in the printing direction determined by a probability function and reducing the grey level of those certain pixels below a second threshold value so as to prevent merging of drops in the printing direction.

Abstract: A method for controlling the printing of overlapping swathes, the swathes extending perpendicular to a succession of print lines; for each print line a transition is defined between one swathe and the next, with the location of the transition in the print line varying between print lines, for example varying pseudo-randomly or as a curve extending in the swathe direction.