Printmakers seem to spend an inordinate amount of time explaining their craft. Pencils, paints, canvas, brushes, stone, bronze and the other accouterments of art-making seem readily comprehensible, but an understanding of printmaking is both enriched and entangled by its many forms and ever-expanding techniques.
Let's try to loosen some of the tangle, shall we? I'll start with some definitions for processes, and as time goes on I'll add other terms.
Keep in mind that none of these descriptions is the final word, since printmakers often combine techniques when creating their work. Nor should this be considered a comprehensive list, because at this time I'm only describing techniques that I've personally had experience with. There's plenty out there that I've never encountered! Printmaking is constantly evolving as new processes are developed, and printmakers will always have to explain themselves. It's okay. It's good for us. Really.
Original printmaking techniques
One of the oldest printmaking techniques is relief printmaking, a process that involves creating a matrix (plate or block) in which the parts of the block NOT intended to print are carved away. Only the image area remains raised. Printing involves inking the surface of the block and bringing it into firm contact with the paper, either by running plate and paper through a press or by hand rubbing with a baren (or spoon!). The resulting printed image is the reverse of the carved block. Examples of relief printing include woodcut, linocut, wood engraving, and the humble rubber stamp. (Sample here is a linocut by... me!) If you're still in the dark, I have a bit of an introduction to relief printing over on my website.
Also, check out this Relief printmaking video by the Minneapolis Institute of Art.
In intaglio techniques the image is incised into a matrix or plate. Copper or zinc plates are often used as a surface, and the incisions are created by etching, engraving, drypoint, aquatint or mezzotint. To print an intaglio plate, ink is applied to the surface and then rubbed with stiff cloth to remove most of the excess, leaving ink only in the incisions. A damp piece of paper is placed on top and plate and paper are run through a printing press. Pressure forces the paper into the incisions and transfers the ink to paper. Examples include etching, mezzotint, and some forms of collagraphs. (Example here is an etching by Daniel Hopfer, ca 1470-1536.)
Intaglio printmaking video.
A monotype is a print made by drawing or painting directly on a smooth, non-absorbent surface such as a plate of metal, glass, or plexiglass. The image is then transferred onto paper by pressing the plate and paper together. Unlike other forms of printmaking, which typically create multiples of an image, this process creates individual unique prints because most of the ink is removed during the initial pressing. Subsequent prints from the same painted plate will differ greatly from the first print.
In creating a collagraph, an artist affixes a variety of textured materials to a rigid substrate such as cardboard or wood. Ink or pigment is applied to the resulting collage, and the board is used to print onto paper using either a printing press or by hand. Acrylic texture mediums, sandpapers, string, cut papers, tapes, leaves and grasses can all be used in creating the collograph plate. Ink may be applied to the upper surfaces of the plate with a brayer as in a relief print, or ink may be applied to the entire board and then removed from the upper surfaces as in an intaglio print. Or both! (This simple collagraph sample is something I did 30 years ago, just to get a feel for the process.)
Screen printing is a stencil method of printmaking in which a design is imposed on a screen of silk or other fine mesh, and ink is forced through the mesh onto the printing surface using a squeegee. A screen print might also be called silkscreen or serigraph. Screen printing can be applied to many different kinds of surfaces and is a popular way of printing garments and posters in addition to fine art applications.
Screenprinting video
Traditional lithography uses a greasy substance drawn on a flat stone to transfer ink to paper. When the drawing is complete the flat surface of the stone is slightly roughened, or etched. The stone is then moistened with water. The parts of the stone not protected by the greasy drawing soak up the water and then oil based ink is rolled onto the stone. Ink clings to the greasy drawing and is repelled by the water. Paper is pressed into the stone and voila! An image printed directly from the stone will appear in reverse. Clear as, err... stone, right? There's a great step-by-step example over at How Stuff Works. (This sample is "Self Portrait with Skeleton Arm" by Edvard Munch.)
Lithography video.
Enter the mechanical reproduction...
Here's where things can get confusing. Most books and other types of high-volume text are printed using offset lithography, the most common form of printing production. Offset lithography depends on photographic processes and flexible aluminum, plastic or paper printing plates instead of hand drawing on stone tablets. There are gazillions of images called "lithographs," but many are mechanical reproductions created by offset lithography, not hand-crafted lithographs. (The sample here is a plate from Ernst Haeckel's Kunstformen der Natur of 1904. I think it was done as offset because it was part of a published book. If someone knows otherwise, let me know!)
In the last 20 years or so, we've seen a proliferation of "fine art giclée prints." A giclée print is another form of mechanical reproduction, an image created from a digital source using high-quality inkjet printing. The word "giclée" comes from the French "le gicleur" meaning "nozzle", or more specifically "gicler" meaning "to squirt, spurt, or spray." Many painters, for example, create multiple images of popular paintings by using the giclée process on a variety of surfaces, including canvas. In this case they're not creating original prints, but reproductions of work created in another medium.
What I haven't touched on here are contemporary digital print practices, by which artists can and do create original work. It's not a field I know much about, but as I learn more, I'll add it to the page.
Just in case you missed the references in the text, The Minneapolis Institute of Arts has some GREAT videos introducing original printmaking processes on YouTube. Check them out!
Relief printmaking
Intaglio printmaking
Lithography
Screenprinting