Branches of printmaking

Relief print
Relief prints are made by cutting the image out of a flat surface such as wood, linoleum, plaster, perspex or styrene. The negative, or the non-printing part of the block, is either cut or gouged away, leaving the design standing in relief. The most familiar relief-printing material is wood and woodcut, which appeared in the VIII Century in the East and in the XIII century in the West, is the earliest known relief-printing method. Relief printing lends itself particularly to a bold conception of design, expressed more in areas than lines, although variations can be achieved with textures, a variety of marks made with gouges, chisels, or knives. Wood engraving is a variation of woodcut. The main difference is that, for wood engraving, the block—usually pear, apple, cherry, sycamore, or magnolia—is cut cross-grained rather than plank-wise; on the end-grain block the artist can thus cut freely in any direction, allowing him to do much more intricate work with much finer tools. On most relief prints, the whites appear as the positive image against a dominant black.

Intaglio

Katzheimer master (Lorenz Katzheimer), The temptation of Christ , 1492, burin on copper

Intaglio printing is in technical terms the exact opposite of relief printing, because the ink is trapped in the hollows below the surface of the plate. The design can be cut or scratched by a hard tool like a burin (engraving) or etched by a mordant (etching) so to get incisions or grooves, where the ink will be rubbed in and the surface wiped clean. Unlike surface printing, intaglio - which is actually a process of embossing the paper into the incised lines - requires enormous pressure and therefore cannot be printed without a press. Intaglio processes are probably the most versatile of the printmaking methods, as various techniques can produce a wide range of effects, delicate or bold, fine or coarse.
Etching is a process in which lines or textures are bitten (etched) into a metal plate with a variety of mordants. The metal plate is first covered with an acid-resistant coating, called ground. The design is then scratched or pressed into the ground, exposing the metal in these areas. Finally, the plate is submerged in an acid solution until the desired depth and width in the exposed areas is reached. Although the basic principle of etching is very simple, there are many possible variations that have a strong influence on the final result. The materials themselves offer a wide range of possible variations, including the type of metal, the strength of the mordant, the biting time, the kinds of grounds and the ways in which they can be worked, and, finally, all the possible methods of printing.

Lithography

Odillon Redon, Cyclope, 1883, Lithography

Lithography is based on the fact that water and grease do not mix. The image is drawn or painted on the limestone with greasy litho crayon or greasy black ink, called tusche. At this stage, with litho crayons and tusches the artist can work on a stone as he would on paper. A whole arsenal of effects is available, including pen, pencil, splashing, sprinkling, spraying, texture transfers, and scraping. After the drawing is finished and before etching, the image must be protected from the etching solution by rubbing rosin and then talcum powder on the surface: the acid-resistant rosin protects the drawing; the talcum absorbs the excess of grease, allowing the adhesion of the gum etch to the edges of the drawing. A heavy, syrupy mixture of gum arabic and nitric acid open the pores of the stone, enabling the gum and the grease to penetrate easily. The gum arabic surrounds the greasy sections, forming an insoluble surface film that sticks to the negative areas. This coating around the image repels the water applied during printing and establishes a grease reservoir. It does not smear, and it prevents the seepage that would blur the image. Because of the antipathy of grease and water, the image attracts oily ink but repels water. Thus, when the stone is dampened with a sponge and an ink-charged roller is passed over it, the ink is deposited on the greasy drawing but not on the wet stone. A special litho press transfers the inked image onto the paper through the pressure of a bar covered with leather. This process is entirely different in nature to others techniques, as there are no grooves for the ink to sit. The surface of the block remains in fact completely flat during the entire process. Metal plates (zinc or aluminum) can also be used, and these, too, are satisfactory, yet stone is far superior, particularly for producing subtle tones and details.

Screen Printing

Sarah Sanford, Hidden Chamber, 2005, Colour screen printing

Screen printing is an extremely sophisticated stencil process, developed at the beginning of the XX Century in order to advertising and display work. A few decades later, in the Fifties, fine artists started to use the process extensively, giving it the name serigraphy. The process got its name from the fine woven mesh (originally made of silk) that, when tacked to a wooden frame, serves as a support for a cut paper stencil, which is glued to the silk. Stencils are used to mask out the areas of the screen that are not to be printed. There are many ways of making a stencil, from simple paper cutouts, to light sensitive emulsions, on to which photographic images can be projected. Serigraphic printing consists of forcing ink, by pressing with a squeegee, through the mesh onto the paper sheet. The nonprinting areas of the screen are those protected and blocked. The screen was usually made of fine but strong silk but more and more often is made of synthetic gauzes (nylon, tergal) or of wire gauze (phosphor bronze, stainless steel, nickel) as well as the combination of the two (nylon–copper, nylon–bronze).

Photography applied to printmaking
Since its advent, no fine art could shun the reality of photography and be influenced by it. Printmaking has been deeply affected since the early days of photographic pioneering, far before the debate on originality made the scenario more complex. Even in what, at the first glance, could appear merely as a mechanical process, there is an entire spectrum of possibilities, some of which are quite reproductive while others are creative. In many cases the application of photography to printmaking can be corrupting because it leaves no margin for the artwork and brings back a servile idea of printmaking as a medium to "produce" many copies of something. On the other side, when the two media are used and combined in order to achieve a richer vocabulary, the results are nearly limitless.

Non-toxic printmaking
In the most recent years, people gradually increased their concern about safety issues and their sensibility towards the environment. Traditional printmaking involves highly toxic or harmful chemicals and solvents and thus a complete rethink of the processes is due. Yet, it is important to underline that at this stage there is not such a thing as a non-toxic printmaking. Any process that involves chemicals cannot be called safe, plus even the use of the most banal substance can still encounter personal allergic reactions or bad tolerance if not properly used. In honest terms, the situation today reports that, besides what are loosely termed as traditional methods, many workshops have simply introduced acrylic resists, water based inks and substituted the use of acid with salts, with the advantage that they do not release fumes but are equally corrosive. Unfortunately the prints released with these new materials are not always as appealing as those released traditionally and the spectrum of chances with water-based techniques is not equally ample. Therefore, what is important is not to stop the researches and try to work sensibly, with constant awareness of what is being used, stocked or discharged. Professionalism and knowledge play an important role in developing confident and expert printmakers.