Process-printing methods are primarily used for commercial reproduction. Today, however, many artists use commercial methods to produce fine art. Silk-screen printing itself began as a commercial process, and today it is one of the most popular techniques in printmaking because its character is well suited for hard-edge geometric images. Photomechanical processes are incorporated in the work of many contemporary printmakers. Linecut
The linecut technique is the simplest and least expensive of all the photoreproductive processes. As it cannot register tone, it is used mostly to reproduce black-and-white line drawings. If tones are needed in a linecut, they are achieved with the use of screens consisting of dots (Ben Day screens). The linecut is similar to the woodcut in that both are used in relief printing.
Linecuts are usually made on zinc plates coated with an emulsion of albumin or gelatin mixed with potassium bichromate. This emulsion hardens on exposure to light. The light passing through the transparent part of the negative hardens the emulsion. The areas of the emulsion that are protected by the black on the negative remain in their soluble state. The plate is then rolled with greasy ink and soaked in water. The unexposed soft emulsion is washed out by the water. The plate is then dried and dusted with powdered rosin, which adheres to the remaining inked emulsion areas. Heating causes the rosin to melt, forming an acid-resistant coating. The plate can then be etched so that the design stands up in high relief. Halftone cut or plate
Halftone is more sophisticated than linecut, since it is capable of reproducing fine tonal variations. The subject is photographed first through a glass plate that has fine lines printed on it at right angles. The result is an image broken up into tiny dots corresponding to the openings in the screen. When printed, these dots create the optical illusion of continuous tones. There are great variations in screens from coarse (50 lines per inch) to very fine (175 lines per inch). The selection of the screen is dictated by the paper to be used for printing.
After the photonegative of the image is finished, it is printed on a sensitized copper plate. For halftone work, copper is used because of its ability to record fine details. The procedure of washout and etch is similar to that used with linecuts. Rotogravure
To make a gravure plate, a screen is used that is the reverse of the halftone screen, in that the lines are transparent and the areas between the lines are opaque squares. When the sensitized plate is exposed to light through the screen, the emulsion on the plate hardens under the lines but leaves the squares soft. Then the plate is exposed again through a diapositive (a positive transparency) of the subject. This time the soft emulsion squares harden in proportion to the range of grays. In etching, the softest squares are affected by the acid first and the hardest ones last. The result, after the etch, is a plate covered with squares of equal size but varying depth. As the deep squares hold more ink than the shallow ones, the tones in the reproduction are controlled in the same manner as in all intaglio printing methods. The rotogravure plate is inked by an ink-carrying cylinder and wiped by a steel blade that removes all the excess ink from its surface.
Although rotogravure is an intaglio printing process, it is printed on dry paper with light pressure and thin ink. Hence, there is hardly any embossing. Offset lithography
Offset lithography is the application of lithography to commercial mass production. The plate, instead of being a stone, is of specially treated zinc or aluminum, suitable for mounting on a cylinder. The image is photographed on the sensitized lithoplate through a screen. The offset method involves double printing. The image from the plate is printed on another roller covered with a rubber blanket, and from this roller it is transferred to the paper. Because the image is reversed twice, the final print corresponds to the original plate. Since the litho offset ink is thin, to speed up inking and facilitate transfer, the tonal areas lose some of their richness and tend to print gray. Litho offset is often used for colour printing. The colour separation is made photographically. Contemporary experimentation
One of the most crucial changes in the 20th century involved the size of the print. All through its history, with few exceptions, the print was considered an intimate art form, enjoyed by the few. The change started with the Lautrec posters: the print started to grow until it became mural size. As the dimensions of the print changed, so did its character. It became increasingly bolder and more colourful. Today, the print often competes with painting, a situation deplored by many people who feel that in the process the print is losing its particular character and beauty. For a time, major print shows tended to exhibit only a limited number of small, delicate prints, but two more recent developments seem to be balancing that trend. One is the reappearance of the intimate, introspective, black-and-white print. The other is the revival of the long-neglected woodcut, due particularly to the interest of the Postmodernist artists in German Expressionism.
Next to the size of the print, the greatest change has been in the technology of colour printing. In this area, techniques have become so varied that practically any effect is possible. This development has contributed to the vitality of printmaking, because it has encouraged the participation of colour-oriented artists. The combining of various media is closely related to the experimentation in colour printing. Each medium has its own capabilities and limitations; combined, the media often complement each other. It is now common to see three or four different techniques combined.
Another area of experimentation is in three-dimensional surfaces. The trend started with embossing, and today artists are creating completely three-dimensional printed objects.
The shaped print is a printed paper sculpture, made by cutting and folding the printed paper or by assembling precut printed surfaces. Many of these surfaces are metal or plastic objects with printing, usually done by the silk-screen process.
Instead of using rectangular painting surfaces, many painters now work on shaped canvases. In the same way, printmakers, instead of using rectangular plates, are using many different shapes. Printing with movable plates, which became particularly popular in intaglio colour printing and with colour woodcuts, is the logical extension of this freedom. In this method small cutout plates are placed on top of larger plates and printed together, or they are assembled on a cardboard support and printed. This procedure facilitates the use of many colours and also offers great freedom in composing.
Photography is profoundly affecting printmaking. Photographic methods can be combined with intaglio, lithography, or silk screen to enrich their vocabulary. The possibilities are nearly limitless. Yet photography can be corrupting when it reintroduces reproductive ideas, and, unfortunately, it is often used for this effect.
Kinetic (moving) art, such as the mobile, is a major contemporary preoccupation in painting and sculpture. At present there are few attempts in this direction in printmaking, but there will probably be more. The problem in such works is how to combine the print with motion without destroying its very nature. Mounting and care of prints
Very few people know how to display prints and how to take care of them properly. It is heartbreaking to see a great master’s print glued to a cheap cardboard or the border of a fine print ruined with tape.
Because paper, particularly old paper, is fragile, it should be handled as little as possible and never picked up with one hand since this might put too much stress on the paper and tear it. To protect it, a print should be mounted as soon as possible.