Photosensitive polymer plates are used in advanced letterpress printing machines. The image area (ink bearing area) on the cliché is produced by photographic or direct imaging methods. The cliché, which is exposed to light, is then washed with special solutions (chemicals and water-based). Thus, areas that will and will not carry the image appear.
The cliché is placed on the machine by attaching it to the printing cylinder. During printing, the raised surface is covered with ink and then transferred to the printing paper. UV ink and UV drying system are generally used in letterpress printing technique for self-adhesive labels.