Definition: Term derived from the English "to set off". Offset is a printing process developed between 1904 and 1910 without relief or visible hollows, derived from lithography. Stalled on the rotary press, the permanently wet offset plate accepts ink only at places bearing the design: lines of characters, illustrations. Its imprint is transferred onto a rubber-lined cylinder or "blanket", alone in contact with the paper. The web offset press therefore involves three types of back pressure cylinder. Nowadays, it is the most used printing process because it adapts to many different media. For example, dailies, packaging, advertisements, books or catalogs. Its low cost does not detract from the quality of its attentions.