The system of offset printing plates is based on the same principle laiying down printing lithography.

However, while the lithographic printing happens directly (ie, with a direct contact between the stone or the microgranite aluminum sheet and the printed surface), the offset printing plates is defined as a process of indirectly printing. In the offset printing plates, in fact, the printed surface does not come into direct contact with the plate.

The ink transfer happens through three cylinders in contact one another, that act as intermediaries between the matrix and the paper. The presence of an intermediate surface of rubber allows the absorption of water and fats that could affect the print quality and the images yield.

The offset printing plates offers considerable advantages: a high image quality, speed and simplification of the processes of production and printing, long-lasting and efficiency of the platen press that, unlike the lithographic printing process, does not provide direct contact between the plate and the printed surface.