Abstract: A method of generating data for driving an ink jet print head having a plurality of nozzles to print a portion of an image comprising a plurality of pixels comprises storing nozzle position data defining spatial positions of the nozzles with respect to the print head in terms of pixel offsets from a reference position on the print head; reading image data for the image, the image data comprising data for the plurality of pixels; inputting head position data defining a position for the print head; and processing the image data using the head position data and the nozzle position data to determine nozzle firing data for controlling the print head to deposit ink at the spatial positions of the nozzles with respect the head position in accordance with the image data.