Abstract: A method for manufacturing relief printing plates made of a photo-sensitive polymeric material, including the steps of providing a photographic negative having opaque areas and transparent areas defining a desired printing relief pattern, applying a layer of viscous photo-sensitive resin on the photographic negative, providing a flexible support base having a roughened surface, and applying it onto the layer of viscous resin with the roughened surface contacting the layer of resin, projecting ultra-violet radiation on the negative for hardening any of the resin which is exposed to the ultra-violet radiation through the transparent areas of the negative thereby forming the printing relief and causing the resin to adhere to the roughened surface during the hardening thereof, and removing the negative and recovering any of the resin which was behind the opaque areas of the negative and was not hardened.