A method for determining a printing position, such as for image-on-paper registration in a printer or photocopying machine, is disclosed. A fiducial mark pattern comprising a plurality of fiducial marks at predefined relative distances is provided on a printing medium, and is scanned. The fiducial marks and a first edge of the printing medium are identified in a scanned representation of the printing medium. A first distance between the first edge and a first fiducial mark is determined, and a second distance between a second fiducial mark and a third fiducial mark are likewise determined from the scanned representation of the printing medium. The distance between the fiducial mark pattern and the first edge is computed based on both the determined first distance and the determined second distance. The invention also relates to a corresponding system and a computer-readable medium for determining a printing position.