Collector 4 stamps - 55 years of printing - Offset

In 1970, the stamp printing plant was set up in Périgueux (24). Since then, a host of specific printing techniques and historic and modern machines have been put to work for philately and secure products. To mark the Imprimerie's 55th anniversary, a series of 4 collectors illustrate the historical and modern machines and 4 printing techniques used at the Boulazac (24) stamp printing works. This second collector illustrates offset printing. Offset printing made its debut at the Boulazac printing works in 1987 with the stamp commemorating Hugues Capet's accession to power in 987. A photomechanical printing process without intaglio or relief. The offset process was introduced in the 1980s. Its success is due to its flexibility and ability to adapt to a wide variety of products. The image is first engraved with a laser by a Computer to Plate (CTP). It is then translated into a raster (dots of different sizes) on a photosensitive aluminum plate (as many plates as there are colors). The quality of the printed image is determined by the closeness of the dots. On the machine, the inked parts of the plate are transferred to the paper. To obtain the printed visual, the offset operator marks the different colors and plays with the density of the inking. Stamps - DG Press 2023 web offset press, 7 colors. - Offset sheet-fed Man Roland 2013, 6 printing units.

Conception Sylvie Patte et Tanguy Besset (c) La Poste