1. A method for reducing banding artifacts for bi-directional multi-pass printing on an inkjet printer utilizing a printhead with a plurality of ink nozzles comprising: a) defining different print masks to be used for leftward and rightward printing passes such that the order of ink laydown is constant for all vertical and horizontal positions within the image, and wherein the timing between ink laydown on different leftward and rightward passes is constant for all vertical positions within the image at a particular horizontal position; and b) printing an input image on the inkjet printer with the defined print masks using a bi-directional multi-pass print mode; wherein if the print mode has an even number of printing passes, the print mask defined for leftward passes uses a first set of active ink nozzles that excludes a first plurality of contiguous ink nozzles on one end of the printhead, the first plurality of contiguous ink nozzles extending to and including the ink nozzle at the extreme end of the printhead, and the print mask defined for rightward passes uses a second set of active ink nozzles that excludes a second plurality of contiguous ink nozzles on the other end of the printhead, the second plurality of contiguous ink nozzles extending to and including the ink nozzle at the extreme other end of the printhead; and wherein if the print mode has an odd number of printing passes, the print mask defined for one printing direction uses a first larger set of printing nozzles and the print mask defined for the other printing direction uses a uses a second smaller set of printing nozzles together with two subsets of non-printing ink nozzles, one on either end of the printhead, the subsets of non-printing ink nozzles extending to and including the ink nozzles at the respective extreme ends of the printhead.