Offset is a printing technique based on basically the same principle as lithography (there is also a much less common dry offset or offset technique that uses embossed dies). Instead of printing the sheet in direct contact the aluminum plate, printing is done through the use of three cylinders in contact with each other.

It is therefore an indirect printing: this means that printing does not take place, as in the other types of direct printing, by directly transferring ink from the plate (matrix) to the substrate, but it takes place with the ink being carried back from the lithographic plate to the blanket-covered cylinder, and from this to the paper.