Abstract: A method for printing a pattern from a hologram mask into a photosensitive layer on a substrate, which method includes arranging the hologram mask on a coupling element, arranging the substrate so that it is substantially parallel with the hologram mask and separated from it by an amount substantially corresponding to the focal distance of the hologram mask, reconstructing the pattern recorded in the hologram mask by scanning an exposure beam of substantially collimated across the hologram mask while continuously measuring the local separation between the hologram mask and substrate in at least two locations where the pattern is being reconstructed by scanning at least two focus beams across the hologram mask, and continuously adjusting the separation and the angle of tilt between the hologram mask and substrate in order that the pattern reconstructed from the hologram mask is accurately focussed onto the photosensitive layer on the substrate.