a relief print master is created by a printhead that moves in a slow scan direction . the nozzles of the printhead jet droplets of a polymerisable liquid on a rotating drum . the different nozzles jet droplets simultaneously on different layers that have different diameters . as a result , the droplets jetted by different nozzles travel over different distances before landing . the effect of this is that the droplets undergo different position lag as they land on the different layers . by rotating the printhead in a plane that includes the central axis of the rotating drum and a nozzle row this effect can be compensated for .