There are several processes that are commonly used to create prints.
Relief (woodcut, collagraph, linocut)
Here the non-image areas of a plate are cut away or the image areas are built up (or some combination of the two). The high spots are inked, the paper is pressed against the plate and the sandwich is run through a press or a baren is used to rub the paper into close contact with the plate by hand.
Intaglio (pronounced in-tal-yo)
This includes etchings, engravings, aquatint, spirit tint, mezzotint, drypoint and drillpoint. Here a plate (usually metal) has the image cut or etched with acid into it. Ink is applied to the entire plate and then it is wiped off, leaving ink in the grooves. The paper is applied and run through a press under very high pressure.
Lithography is based on the idea that grease and water don’t mix easily. The image is drawn on an aluminum plate or a stone with a greasy pencil or ink. The non image areas are then treated with a chemical that attracts water. The plate (or stone) is inked by wetting the surface and then running the inked roller over it. The water film on the non-image areas rejects the ink while the greasy image attracts it. The paper is applied and run through a special press under extremely high pressure. (Offset lithography, used in creating reproductions, uses the same basic process except that the plate is mounted on a drum, which is rotated past wetting and inking rollers and the ink image is transferred to rubber blanket attached to a different drum and transferred from there to the paper. This happens at high speed)
In this process a stencil is applied to a fine mesh stretched on a frame. The frame is placed against the paper and the ink is squeeged through the stencil. This is the same basic process used to create t-shirts, but the inks and papers used are obviously different.
Monotype & Monoprint
In a monotype, the image is drawn directly on a blank plate with ink and a single proof is pulled. Sometimes a ‘ghost image’ is pulled on a second sheet of paper with the ink that remains on the plate. For a monoprint, the plate contains at least a partial image and the hand additions modify that image.
This process is usually combined with intaglio. Here bits of colored paper or other prints have glue applied to them and they are applied to an inked plate which is then printed on a larger sheet. The pressure of the press glues the paper down tightly and the ink from the new image overlaps the other papers.
This includes a wide variety of techniques including carborundum prints. Here the artist begins with a blank plate (wood, metal, plastic) and builds up the image on it by gluing, adding gel media, etc. The resulting plate may be inked and printed either as a relief plate (ink rolled on the high spots) or as an intaglio plate (entire plate inked and ink wiped off of the high spots and flat areas).