Glossary

Words set in CAPITALS are defined elsewhere in the Glossary.

Acid Bath An acid solution contained in a shallow tray in which metal plates are immersed for ETCHING.

Agate A very hard shaped stone mounted in a wooden handle, used primarily to burnish paper, thin foil, and silver or gold leafing. Agates come in beveled flat, blunt rounded, and curved rounded shapes. See also Burnisher.

“A la Poupée” Method An intaglio technique for hand-depositing more than one colour of ink onto a printing plate using a TARLATAN, BRAYER,brush, DABBER,or a combination of these, and printing the colours simultaneously. Stencils are often used when inking the plate to position the colours accurately. This method is sometimes called dolly printing. At the workshop it is commonly referred to as MULTIPLE–INKING TECHNIQUE.

Alum A complex salt, essentially a hydrate of potassium aluminum sulfate, used along with rosin in the SIZING of paper and as a MORDANT for fixing colours. Also called papermaker’s alum.

Aniline Dye A dye of coal tar origin discovered by William Henry Perkin in England in 1856. Aniline dyes are prepared from benzol, which is a product of coal tar. Today the term is used broadly to designate synthetic organic dyes and pigments. A class of aniline dyes called direct dyes or substantive dyes have a high affinity for cellulose and are used to colour paper pulps. Acid dyes are another class of aniline dyes that have no direct affinity for cellulose and require a MORDANT to fix the colours to the fibers. Acid dyes are used in surface colouring of paper.

Aquatint An INTAGLIO technique in which fine particles of acid-resistant material (powdered rosin, spray lacquer, or spray paint) are adhered to a plate to create tonal effects. The plate is first treated in an ACID BATH like an etching plate. Afterward the acid-resistant material is removed. The resulting etched, or bitten, surface produces a textured area rather than lines. An aqua-tint plate can be used to print even tones or tones with gradation or blending effects. Aquatint is often used in combination with other intaglio techniques. The aquatint process using a rosin ground was invented by the Frenchman Jean Baptiste Le Prince around 1768.

Aquatint Chamber A chamber containing a shelf on which printing plates are placed to receive an even ground of rosin particles for aquatint processing. A paddle wheel or air device is used to circulate the rosin particles in the chamber, and while the particles are still airborne, the printing plate is placed on the shelf to receive the falling rosin. See also Dust Bag.

Archive Copy The print impression retained by the publisher as a permanent archive. In 1984 the McKnight Print Study Room was established at the Walker Art Center to house and maintain the Tyler Graphics Ltd. archive collection.

Artist’s Proof A PROOF outside the numbered EDITION but equal in quality to it. Each artist’s proof is inscribed by the artist Artist Proof or A.P. and consecutively numbered (e.g., 1/20, 2/20, etc., or I/XX, II/XX, etc.).

Asphaltum A greasy bituminous liquid used as an acid resist in INTAGLIO and for processing printing elements in LITHOGRAPHY. It is sometimes used as a drawing medium on stone and metal plates.

Assembled Plate A plate composed of parts such as fragments of manufactured objects, printing elements, FOUND OBJECTS, or other materials. The parts are attached or mounted on a rigid backing to form a single composite PRINTING ELEMENT or are assembled unattached on the press BED for printing. Assembled plates are made for EMBOSSING, INTAGLIO, and RELIEF PRINTING.

Bast Fiber A term commonly used to designate fibers obtained primarily from the inner bark of plants and trees. FLAX, GAMPI, HEMP, JUTE, and MITSUMATA are typical bast fibers. The bast fiber from various mulberry trees in the Far East is generally referred to as KOZO fiber.

Beater A machine designed to treat FIBERS for papermaking. A rounded oblong tank is partially divided by a vertical wall (midfeather). Mounted in the tank on one side of this wall is a heavy horizontal roll that revolves against a bedplate recessed in the bottom of the tank. Both the roll, which can be adjusted vertically, and the bedplate contain horizontal metal bars set on edge. These two units serve as impellers to circulate the water and pulp mass in the tank while passing it between the metal bars to cut, macerate, bruise, and separate the fibers during the beating operation. Beater designs vary, but the principal function is the same. The machine is sometimes called a Hollander, from the place of its invention in the late seventeenth century, when it began to supersede the stamper (stamping mill), which had been used in Europe since the twelfth century.

Beating The principal operation involved in the preparation of FIBERS for papermaking, used both to control fiber length by cutting and to hydrate fibers by bruising or abrasion. Also used to mix additives (such as dyes, pigments, SIZING, or fillers) with the fiber and water SLURRY.

Bed The flat surface of a flatbed press, which carries the PRINTING ELEMENT.

Bevel The hand-filed or machined angle on the edge of a metal plate which prevents injury to the BLANKET and damp paper during the printing process. The bevel produces a distinctive embossed PLATE MARK on the print.

Blanket In INTAGLIO, the felt material placed between the paper and the press roller during printing in order to distribute pressure evenly over the plate surface, to prevent shifting of paper, and to provide cushioning and aid in pressing the paper into the lines of the plates. In OFFSET LITHOGRAPHY, the resilient rubberized covering of the press cylinder, which receives the ink impression from the plate or stone and transfers it to paper. See also Felt.

Bleed In printing, to print an inked impression beyond one or more edges of the paper. In papermaking, bleeding refers to the oozing of coloured dyes from PULP that has been pigmented, which can occur before or after pressing. Bleeding can be regulated by adding a MORDANT to the pulp mixture.

Blend Inking A technique of consistently rolling out on a slab a set pattern of several different coloured inks in such a way that the blend can be transferred identically to the PRINTING ELEMENT for each impression. This method of inking, usually referred to as a split ink fountain, can also be employed using the oscillating ink rollers of an offset press or VANDERCOOK PRESS. Blend inking can be achieved in screen printing by pressing several different coloured inks through the screen with one wipe of the SQUEEGEE. Also called rainbow roll or spectrum roll.

Blind Printing Printing from uninked plates to create three–dimensional form.

Blockout In screen printing, any material, such as paper, film, tissue, glue, lacquer, or a photographically made stencil, that is applied to the screen fabric to prevent the penetration of ink. See also Knife-cut Stencil.

Blockout Compound A tough, elastic, fast-drying liquid screen filler for blocking out screens. The three kinds of blockout compounds generally used are the water–soluble, solvent–soluble, and solvent–resistant types.

Blockout Stencil Broadly speaking, all methods of stencil making employ blockout. The shop term blockout refers specifically to a stencil-making procedure in which a hard-drying fluid, such as lacquer, BLOCKOUT COMPOUND, or glue, is applied with a brush or spatula directly to the screen, selectively blocking out areas and preventing the penetration of ink during printing. Multiple printings from one stencil are achieved by masking selected areas of the stencil for printing, removing the blockout from the stencil, masking adjacent areas, and printing again. This technique is used when precise registration is required in colour printing.

Blow Up To enlarge pictorial material by hand or photographic methods.

Brayer A small ROLLER fitted with a handle and used for applying ink to a PRINTING ELEMENT.

Brightness A term commonly used in the paper industry to describe the reflectivity of white papers or pulps under specific conditions and with a specific light source. Specialized laboratory instruments are used for measuring brightness, which is related to, but not a measure of colour. Brightness is the underlying reflectivity of paper in light. Measurement readings are expressed in relation to a known standard. A general guide to brightness readings follows. 100% brightness: magnesium-oxide standard
90%—95% brightness: fine mould–made print paper
85%—88% brightness: machine–made book paper
65%—68% brightness: newsprint

Bulk The thickness of paper expressed in terms of the number of sheets (or pages) per inch or centimeter under a specified pressure. See also Caliper.

Burin An engraving tool used on metal plates or woodblocks, consisting of a partially rounded wooden handle attached to a square or lozenge-shaped metal shaft, sharpened to an angle of approximately 45 degrees. A version of the burin is made with a varying number of tiny points machined into the conventional angle used for making multiple lines. These tools are made in a number of sizes. Also called a graver.

Burnisher A highly polished steel tool made in a variety of shapes: single or double ended, flat, spoon shaped, conical or combined with a SCRAPER. A common type of burnisher has a round shaft mounted in a wood handle with one end of the shaft slightly flattened, tapering to a blunt point, and curving upwards. Used for repolishing the surface of a plate after scraping and for lightening tonal areas in AQUATINT, MEZZOTINT, or SOFT GROUND. An alternative method of burnishing makes use of a small power tool with buffing wheels and polishing compound or abrasive hones. See also Agate.

Burr Metal ridges forced up on one or both sides of the scored line in DRYPOINT or the cut line in ENGRAVING and forming the “tooth” of the roughened mass in MEZZOTINT. The burr is usually removed in engraving but retained in drypoint. In mezzotint the burr forms the entire surface of the plate after it has been worked by the ROCKER. The burr holds additional ink during printing and imparts a velvety look to the printed line or surface. The abrasiveness of inking and the pressure of the printing press contribute to the rapid disintegration of the burr; consequently number of high–quality impressions that can be taken from such a plate is limited. To increase the run, plates are often steel–faced before printing. See also Steel Facing.

Calendering The process of flattening and polishing paper to regulate its tooth or texture. A necessary step in preparing paper for certain printing processes, calendering influences the paper’s receptivity to ink andhelps to determine whether a paper will work in a printing operation. A calendered finish is achieved either by pressing individual sheets of paper in a LITHOGRAPHY PRESS between the press BED and TYMPAN or by running paper through a series of polished rollers, which compress the paper as they smooth the surface

Caliper The thickness of an individual sheet of paper usually expressed in thousands of an inch or millimeters.

Cancellation Proof A print made from defaced PRINTING ELEMENT of an EDITION. In multicoloured prints the practice is to cancel only one of the elements. Cancellation proofs give collectors a guarantee that no additional images will be pulled and are signed or initialed and dated by the artist. When no cancellation proof is made for a given edition, the workshop notes the reason.

Carborundum The trade name for a powdered abrasive made from a hard compound of carbon and silicon, used for GRAINING lithography stones.

Casein Paint Paint made from pigment mixed with a binder made from casein, a protein found in milk. These paints are very opaque and dry to a mat finish. They can be thinned with water and, when dry, cannot be rewetted.

Cast Paper A type of three–dimensional paper made by dipping a shaped MOULD into a vat of PULP or by pouring, spooning, or patting pulp in or around a shaped mould. Once the pulp has dried it is separated from the mould. Moulds for cast paper can be constructed from a variety of materials, including FOUND OBJECTS. Shaped wire or plastic screening is the best material to use when moulds are dipped. Other methods of making cast paper employ moulds constructed from plaster, rubber, wood, and ceramic. One variation of cast paper is to laminate a newly made sheet over a mould and hand–press it into shape.

Chemical Cotton A term used in the paper industry for purified cotton linter pulp, the purest form of cellulose commercially available. Chemical cotton is available in various fiber lengths and as loose pulp, laps, rolls, or cut sheets. In preparation of the pulp in sheets, a higher proportion of shorter fibers may be present than in loose pulp.

Chemical Pulp A PULP made by cooking wood chips with steam and chemicals under high temperature and pressure to remove impurities, principally lignin, which deteriorates rapidly on exposure to light and air. Highly purified wood pulps, such as those used for rayon manufacture, are obtainable and are sometimes called high–alpha pulps.

Chine Appliqué A method of adhering one sheet of material (often thin paper) to another with glue under pressure. Paper used for this purpose has already been formed and dried. See also Collage.

Chine Collé A method of selectively adhering a thin sheet of paper to a larger and heavier sheet using glue or GUM ARABIC during the printing process. Traditionally a thin, fragile Oriental paper with excellent printing qualities was adhered to a heavier European paper for added strength and colour, and the printed image was designed to cover only the Oriental paper. This method is rarely used by the workshop and has been replaced by the technique of collaging papers before printing, which guarantees paper registration and uniform surface quality See also Chine Appliqué.

Chisel The principal tool for shaping and cutting wood, LINOLEUM,or metal. Constructed of a blade with a beveled edge mounted in a wooden handle, chisels are made in different sizes for removing material by hand with the aid of a hammer.

Chop An identifying mark used by printers, artists, print workshops, and publishers. Chops are made as stamps and as embossing dies for marking prints.

Collage A technique introduced into fine art by Georges Braque and Pablo Picasso about 1909, in which fragments of commercially printed paper were incorporated into compositions. Collage was later developed by the artists of the Dada and Surrealist movements to include FOUND OBJECTS. Today any material fixed to a surface may be termed collage. See also Chine Appliqué.

Colophon A brief statement usually placed on the last page of a book or portfolio, which often includes information on the typeface and design, the paper and printing techniques used, and other facts of production.

Coloured, Pressed Paper Pulp A term used at the workshop to refer to the use of dyes or dyed pulps in the making of unique handmade papers. colour is either added to the FURNISH in the VAT, applied directly freehand, or applied with the aid of a device such as a COOKIE–CUTTER MOLD, template, straightedge, or temporary frame placed on the newly couched or hand-cast pulp. This process often results in the creation of one–of–a–kind papers. See also Coloured Pulp; Embedding; Mixed Pulp; Staining; Vacuum Forming.

Coloured Pulp A SLURRY that has any type of colouring matter, such as pigments, dyes, paints, or coloured rags, added to it to make coloured paper. coloured pulps may be intermixed in the BEATER, in the VAT,or in small containers to make uniform or nonuniform coloured paper. See also Coloured, Pressed Paper Pulp; Mixed Pulp.

Colour Trial Proof A PROOF made before the colours to be used in an EDITION have been determined. The proofs are inscribed colour Trial Proof or C.T.P. followed by an Arabic or Roman numeral.

Composition Roller A type of ROLLER believed to have been invented in the early 1800s in England by Augustis Appligath. Nineteenth–century rollers for hand and machine lithographic printing were made from a mixture of glue and molasses poured into a metal mold encasing a wooden roller. Today composition rollers are made from a variety of rubber and plastic compounds.

Contact To bring artwork and the printing side of a PLATE or screen into contact for exposure in a VACUUM CONTACT FRAME.

Continuous–Tone Film A film without a halftone dot screen used to make a printing plate in which the drawn image presents all of the gradations of tone from dark to light, as in a wash drawing.

Continuous–Tone Image An image with gradations of tone from dark to light like a wash drawing and unlike an opaque drawing, which has no gradations.

Cookie–Cutter Mold A thin–walled sectioned plastic or metal mold used for colouring newly formed wet sheets of paper with pigmented pulps and dyes. The mold is registered on top of the newly made wet sheet, and PULP is spooned or hand-patted into the sections. The mold is then removed, and the applied COLOURED PULP is fused with the base sheet as it is pressed between blotters and FELTS in a PLATEN PRESS. The paper is then dried on screen trays or blotters. See also Coloured, Pressed Paper Pulp.

Cotton Fibers The long, flat tubular fibers of the cotton plant, which grow from the end of the cotton seed as single slender hairs. Cotton fibers are the purest form of cellulose used in papermaking. These opaque white fibers produce a paper that is soft, flexible, and bulky. For papermaking, cotton may be used in the form of rags, LINTERS, or, less commonly, long-staple fibers. Cotton plants are cultivated principally in India, Egypt, and the United States.

Couching Transferring the wet, newly formed sheet of paper from the MOULD to a wet FELT using pressure. Two or more newly formed sheets can be couched together to form a multilayered sheet. See also Cast Paper; Duplex Paper.

Counteretch (1) To pretreat a plate or stone in order to clean and desensitize the surface. (2) To resensitize the nonprinting areas of a PRINTING ELEMENT to prepare for the addition of new image areas.

Counterproof A printed proof offset onto another sheet of paper. The resulting image is reversed in relation to the printed proof but is identical to the plate it was printed from.

Curating The procedure performed by the curator and the printers to prepare a predetermined number of prints for signing by the artist. This entails careful inspection of the paper and printed surface for any defects or deviations from the RIGHT TO PRINT standard established for the edition by the artist and the workshop director. The prints are then collated into an EDITION with proofs and signed. Finally each impression is marked with the workshop CHOP and numbered on the verso with the workshop number. See also Print Documentation.

Cylinder Mould Machine The mechanism used for making MOULD-MADE PAPER, consisting of a wire-covered cylinder that revolves in the VAT. Fibers cling to the cylinder, while the water is strained through. The cylinder mould machine was first patented in France in 1807 by a Frenchman from Normandy named Desestables.

Dabber A mushroom-shaped device consisting of a wooden disk covered with leather, silk, or felt and attached to a handle. Used for spreading ink over a printing surface or for laying wax grounds on plates. Simple disposable dabbers are constructed from rolled felts taped together.

Deckle A wooden frame, separate from the MOULD, which acts as a rim. It controls the size and shape of the sheet of paper and the thickness or amount of pulp on the mould.

Deckle Edge The rough edge on handmade paper. Originally considered an imperfection and cut off. However, the deckle edge came back into fashion in the late nineteenth century with the handicraft revival. Many handmade sheets made today have very pronounced irregular deckle edges, which some artists and printers consider attractive.

Desensitizing The chemical process in LITHOGRAPHY in which the nonimage area of a plate or stone is made nonreceptive to ink (hydrophilic) through GUM ETCH treatment of the surface.

Developing For plates, a chemical process that removes the unhardened bichromated coating from the exposed plate in three stages: (1) it makes the image ink receptive (oleophilic), (2) desensitizes the nonimage areas, making them water receptive (hydrophilic), and (3) gums the surface in preparation for printing. For screens, the chemical process that further hardens the nonprinting areas of the stencil before washout. The film is first exposed, then developed and WASHED OUT. See also Exposure.

Diamond Point A DRYPOINT NEEDLE fitted with a diamond tip, used primarily for drypoint drawing.

Diazo A photosensitive chemical used in photographic emulsions for making light-sensitive lithography plates. Diazo compounds were discovered in Germany in 1858, but no real advance in their use was made until the late 1920s. See also Presensitised Plate; Wipe-on Aluminum Plate.

Die Stamping The use of a die of brass, zinc, or other hard metal to stamp an image into material such as the cloth spine of a portfolio. Die stamping may be done without ink, with ink, or with foil.

Direct/Indirect Photographic Screen Stencil A screen stencil that combines features of both the direct and indirect photographic screen stencils. The six steps for making this type of stencil are: (1) indirect photographic film is placed, emulsion side up, on clean paper; (2) the printing side of the screen is placed on top of the unsensitized film; (3) direct-type light-sensitive emulsion is squeegeed across the screen fabric, adhering the film below; (4) the fabric-emulsion-film combination is dried in a horizontal position using a fan; (5) the film support sheet is peeled away. The positive image is contacted to the printing side of the coated screen in a VACUUM CONTACT FRAME and exposed; and (6) the unexposed emulsion is WASHED OUT, leaving the hardened emulsion on the screen fabric as the stencil. See also Blockout Stencil; Direct Photographic Screen Stencil; Indirect Photographic Screen Stencil.

Direct Photographic Screen Stencil A direct stencil made by applying a liquid photographic emulsion to the screen. To make the stencil, both sides of the screen fabric are hand-coated with positive- working light-sensitive emulsion and dried. The positive image is then contacted to the printing side of the coated screen in a VACUUM CONTACT FRAME and exposed. The unexposed, soft emulsion is WASHED OUT with water, and the exposed, hardened emulsion remains on the screen fabric, forming the stencil. See also Blockout Stencil; Direct/Indirect Photographic Screen Stencil; Indirect Photographic Screen Stencil.

Direct Printing Press See Lithography Press.

Direct-Resist Magnesium Plate The result of a direct method of relief platemaking, in which an acid-resistant material is drawn on a polished magnesium plate, dried, and exposed to intense heat, which further dries and hardens the drawing material. The plate is then processed into a relief element using a POWDERLESS ETCHING process. The raised level of the plate can be inked with a roller to print as a relief, or the recessed level can be inked and wiped to print as an ETCHING. When these two inking techniques are combined on one plate, the print is an etching made from intaglio and relief surfaces.

Drypoint An INTAGLIO process in which marks are made on a plate with a sharp, pointed instrument. This tool creates a ragged curl, or BURR, on the side or sides of the incised line. Both the incised line and the burr receive ink when the plate is wiped, giving the printed line a distinctive velvety look. Drypoint is usually done on copper plates and is often combined with other intaglio techniques, such as ETCHING and AQUATINT. The first artist to work in the drypoint technique was the Master of the Housebook, who worked around 1480 in Germany. See also Steel Facing.

Drypoint Needle A solid steel tool with a tapered point used to inscribe or score lines into metal. See also Diamond Point.

Duplex Paper Two layers of paper, generally of different quality, size, and colour, couched together in the wet state and pressed to form one solid sheet of paper. In commercial papermaking, duplex paper may be formed with two different sides or laminated in the dry state.

Dust Bag A small silk or nylon bag containing powdered rosin, used for laying aquatint grounds. To release the rosin, the bag is held over the plate and gently tapped with the hand.

Dyed Stuff PULP that has organic colouring matter added to the stock in the BEATER. Often the dyes are fixed with a MORDANT to prevent bleeding or to fix the colour on the fibers. Dyed stuffs can be dried for later use as a FURNISH. They are reconstituted using a HYDRAPULPER, beater, or other mixing device.

Edition The series of images identical to the RIGHT TO PRINT proof. An edition of twenty-five contains twenty-five prints consecutively numbered 1/25, 2/25, etc. Edition prints are signed, numbered, and often dated by the artist.

Embedding The application of materials, such as rags, thread, or vegetation, to the surface of a newly couched sheet of paper. If placed in a press with the wet paper, the material becomes an integral part of the sheet, imparting its colour and shape to the paper surface. See also Coloured, Pressed Paper Pulp; Duplex Paper.

Embossing Any process used to create a raised or depressed surface. The techniques of ETCHING,stamping, carving, or casting are most often used to make embossing plates. However, FOUND OBJECTS, male and female dies, and metal rolls with engraved or etched designs can be used to create raised or depressed images or patterns in paper.

Endpaper A folded sheet attached to the inside front and back covers of a book.

Engraving An INTAGLIO technique in which a metal plate is manually incised with a BURIN. The burin is pushed across the plate at various angles and with varying pressure, permitting the cutting action to range from a deep to a tapered stroke. The incised lines vary in width and darkness when printed. The technique of engraving metal dates from antiquity. It was employed by the Greeks, Romans, and Etruscans for decorating objects. It was not until about 1430 in Germany that engraved plates began to be used for making prints.

Esparto A coarse grass native to North Africa, used in papermaking. The grass has short, relatively fine, wiry fibers, which produce a paper with finely compacted FORMATION.

Etching An INTAGLIO technique whereby drawn marks are bitten into the metal plate by chemical rather than mechanical action. An acid-resistant ground is thinly applied to the plate’s surface and dried (except for SOFT-GROUND coatings, which are nondrying). Using various tools, the artist draws through the ground, exposing the metal. The plate is then immersed in an ACID BATH, which chemically dissolves the exposed metal and produces recessed areas in the plate surface. Using stop-out varnishes, selected areas of exposed metal can be etched to different depths. Etching is often combined with other intaglio techniques. The method for etching metal to decorate armor was well known before the fifteenth century. The technique of etching metal plates in order to print from them was not introduced until the sixteenth century in Germany. Urs Graf produced the first dated etching in 1513. See also Foul Biting.

Etching Ground Any acid-resistant substance made from various mixtures of wax, gum, varnish, ASPHALTUM, tallow, and resin. To make an even ground, the mixture is either poured over or painted on the metal plate, forming a coating. It can also be applied to the surface of a warm metal plate with a DABBER or ROLLER, after which it can be drawn through with a variety of tools. Etching grounds are often used to block out areas on an etching plate prior to acid treatment. See also Hard Ground; Soft Ground.

Etching Needle A tool used to draw through the ground on an etching plate. It consists of a light steel rod with a rounded point, set into a wooden holder. Needles can also be made from altered dental tools, sewing needles, and similar objects.

Etching Press See Intaglio Press.

Experimental Impression A unique IMPRESSION pulled to study the effect of a given printing process, which may or may not lead to the printing of an edition. An experimental impression is similar to a MONOTYPE and is often hand–coloured.

Exposure The measured ultraviolet light units from a quartz iodine lamp used to harden light-sensitive coatings on plates or screen–coating solutions in photographic plate and screen methods that use a VACUUM CONTACT FRAME.

Felt A woven textile, usually of wool, onto which sheets of paper are couched. See also Blanket; Couching.

Felt Finish The impression on a paper surface created by pressing wet or partially dry sheets between FELTS.

Fibers The threadlike structures from which papermaking pulp is made; usually cellulose, but in modern usage sometimes synthetic. Cellulose fibers are derived from plants and have the unique property of forming a self-adherent mat when suspended in water. Synthetic fibers do not have this property and require the use of a binder. Fibers are prepared for paper-making in three steps: (1) separation by cooking the raw materials, then separating them mechanically; (2) beating, cutting, and bruising for better coherence and paper formation; and (3) refining and final cutting to optimum length.

Fillers In papermaking, nonfibrous, insoluble materials added to the fiber FURNISH in order to impart specific properties such as opacit improved ink receptivity, whiteness, or surface smoothness. Among the materials used for this purpose are clay and calcium carbonate.

Flat A printing term used to describe an image that lacks contrast and prints as a solid tone.

Flax The BAST FIBER of the flax plant, the source of linen. Either flax fiber or linen rags may be used for papermaking.

Formation The appearance of paper when held up to the light, also called look–through. Formation is related to the evenness of fiber distribution in the sheet. It is influenced by fiber length and hydration (which are controlled by beating and refining), by additives such as FILLERS, and by the way the sheet is formed.

Foul Biting In ETCHING, corroding or pitting of a plate during biting as a result of faulty grounding. These irregularities are often of interest to the artist and may be incorporated into the final print.

Found Object An object found by the artist and employed in its original state or in an altered form in the assemblage of a work. Found objects can also be incorporated into an ASSEMBLED PLATE or used as a surface to print from. See also Collage.

Frisket A piece of paper or plastic film that is placed between the inked PRINTING ELEMENT and the paper to keep areas free of ink during inking or printing. Frisket paper is also used to block out or mask portions of artwork during retouching or airbrushing.

Furnish The mixture of PULP and any other material suspended in water (after the pulp has been prepared in a BEATER or other type of macerating machine), creating a SLURRY from which paper is made. See also Stuff; Vat.

Gampi A BAST FIBER commonly used in JAPANESE PAPERMAKING. Derived from the shrub of the Thymelaeaceae family and characterized by long, fine, tough, glossy fibers.

Ghost Impression A term given to a PROOF pulled after the first IMPRESSION has been taken and before additional inking of the PRINTING ELEMENT. Usually a printing element that has been fully inked to print a good impression has sufficient ink left on its surface to print a very light second impression. With careful manipulation of ink layer and printing pressure, both the original and ghost impressions can be included in an EDITION.

Gouge A tool shaped like a CHISEL with a concave blade used for cutting grooves.

Graining In LITHOGRAPHY, the altering of a plate or stone surface to a rough finish consisting of many thousands of tiny “hills” and “valleys” necessary for holding water and image in the LITHOGRAPHY PRESS. There are a number of manufacturing methods used for roughening a metal surface: chemical graining, sandblasting, ball graining, dry brush graining, wet brush graining, and ball brush graining. For stone graining, a hand–driven or a manually operated and power–driven LEVIGATOR is used with water and CARBORUNDUM abrasive. The workshop uses a custom-made stone-graining machine designed by Kenneth Tyler in 1973, which consists of a power–driven levigator attached to a movable carriage that transverses a flat table that holds the stone for graining.

Graver See Burin.

Groundwood (Mechanical) Pulp A PULP made by grinding peeled or barked logs against a grindstone. Yields are high, but impurities remain. See also Fibers.

Gum Arabic A vegetable gum exuded from the bark of the acacia tree, which grows in the Middle East and North Africa. The gum is the principal ingredient in the manufacture of lithographic plate gum solutions and desensitizing plate etches. Used to “gum down” plates and stones and mixed in various acid formulas for DESENSITIZING plates and stones.

Gum Etch A solution of GUM ARABIC and acid used in DESENSITIZING lithography plates and stones.

Halftone A process whereby a CONTINUOUS-TONE IMAGE, such as a photograph, drawing, or painting, is photographed through a screen made with a graduated dot pattern. The screening simulates grays in printing by reducing the continuous tones to a series of dots. The size, shape, and spacing of the dots vary in direct proportion to the tones they represent. There are two types of halftone screens: ruled glass screens and contact film screens. Screens are defined and classified by the number of dots per linear inch. Fifty-five-, 65-, and 85-line screens contain fewer dots and produce coarser halftones than, for example, 150-, 200-, and 300-line screens. The halftone structure is transferred to a film, from which a halftone printing plate can be made.

Handmade Paper Paper that has been formed from PULP using a hand-held MOULD, matrix, or other device. See also Cast Paper; coloured, Pressed Paper Pulp; Duplex Paper; Vacuum Forming.

Hand-Wiping The technique of removing surface ink from an intaglio plate with the palm of the hand or a soft muslin rag, leaving ink only in the lines and areas to be printed.

Hard Ground An acid–resistant compound that is heated so that it becomes liquid, applied to a warm etching plate with a DABBER, and rolled to a thin, even coating. The coated plate is air-cooled, forming a hard ground. ETCHING NEEDLES or a variety of shaped metal instruments can be used to cut through the ground to expose the metal for ETCHING. Hard ground is often used in combination with other INTAGLIO techniques. See also Etching Ground; Lift Ground; Soft Ground.

Hemp The BAST FIBER of Cannabis sativa, also used to make rope. Can be used for papermaking in raw form or, more commonly, as waste from other processes.

Hog In papermaking, a slow–moving, paddle–wheel–like mechanical agitator that keeps the SLURRY in the vat in constant movement, preventing the fibers from settling.

Hors de Commerce An IMPRESSION pulled outside the EDITION for the personal use of the publisher or artist.

Hot-pressed Used to describe paper with a surface smoothed by hot plates or rollers.

Hydrapulper A cylindrical or cone-shaped vat with a power-driven agitator used to defiber and mix PULP for papermaking. Usually, dried COLOURED PULP is returned to slurry form by adding water and mixing in this machine. See also Beater.

Hydration In papermaking, the process of altering cellulose fibers by increasing their absorption of water. Hydration takes place in a BEATER or other type of macerating machine, and the greater the degree of hydration, the more gelatinous the stock becomes and the slower its rate of drainage on the MOULD. Hydration has an important effect on sheet properties. Increased hydration improves FORMATION and sheet density but decreases porosity opacity, BULK, and ink receptivity.

Hydraulic Platen Press See Platen Press.

Impression A print made by any printing method.

Indirect Photographic Screen Stencil A screen stencil made from a specially prepared presensitized film that is exposed and developed away from the screen and later transferred to the screen fabric as a stencil. The presensitized film is manufactured as a sensitized emulsion on a polyester or vinyl support sheet. The positive is contacted to the emulsion side of the film in a VACUUM CONTACT FRAME and exposed. After exposure the film is developed in a sensitizer bath of hydrogen peroxide solution. Then the unexposed emulsion layer is WASHED OUT with water, and the exposed hardened emulsion layer stuck to the screen is dried with a fan. Once the emulsion is dry, the plastic support sheet is peeled away from the stencil, and all open areas of the screen fabric and pinholes in the stencil are blocked out in preparation for printing. See also Direct/Indirect Photographic Screen Stencil; Direct Photographic Screen Stencil.

Indirect Printing Press A motor-driven machine with two fixed horizontal BEDS, the first bed for the PRINTING ELEMENT, the second bed for the paper or other material to be printed. A pressure unit, termed a carriage, consisting of a series of automatic inking and dampening rollers and a large cylinder (covered with a rubber composition BLANKET), moves back and forth across the two beds under light pressure. It deposits ink and water on the printing element on the first bed from one set of rollers as it passes over, and it lifts off the ink from the stone or plate with the blanket cylinder on its return movement. The blanket cylinder then deposits ink onto the paper on the second bed. The impression, since it is transferred from the printing element to the blanket and from the blanket to paper, is reversed twice and does not end up as a mirror image as it does in direct printing. The indirect printing press is often used where the stone or plate is hand- inked and the paper laid by hand directly on the printing element. The blanket- covered cylinder is then used only to apply pressure for making the impression. This results in a direct printing method. The workshop’s indirect printing press, a specially designed Steinmesse and Stollberg press, prints from litho stone and plate and from any relief printing element.

Ink A printing medium composed of pigment in a carrier vehicle. The pigment may be organic or inorganic; the vehicle may be water, oil, emulsion, or natural or synthetic varnish. In the printing process the ink is a film that splits, one part transferring to the printing substrate, the other remaining on the PRINTING ELEMENT.

Intaglio A printing process in which the image is incised or etched into a metal plate using a variety of techniques and tools. Ink is applied to the recessed areas of the printing plate by wiping, dabbing, or a combination of both. The paper receives the ink from the incised marks and not from the top surface of the plate, although thin films of ink may be left on the surface to produce a variety of tonal effects. For intaglio printing, the paper is dampened so that under printing pressure it will be squeezed into all the inked recesses of the plate and around it (leaving a PLATE MARK if the plate is smaller than the paper). One of the distinguishing characteristics of this type of printing is that the dried ink impression stands up from the paper in very slight relief, perceptible by touching with the finger or by close inspection. AQUATINT, ENGRAVING, ETCHING, MEZZOTINT, and DRYPOINT are intaglio techniques.

Intaglio Press A hand or motor-driven machine constructed of a flat BED that moves between two large cylinders of equal size. For printing, the inked plate is placed on the bed, then paper is laid on top of it and covered with a felt BLANKET. These elements are run through the two cylinders, which apply pressure, creating the impression.

Japanese Papermaking Two ancient methods are employed in the making of washi, Japanese handmade paper, called tame-zuki and nagashi–zuki. Tame–zuki originated in China around A.D. 100 and spread to Korea, Japan, and the West. Western handmade papers are made the tame–zuki way using different PULPS and MOULDS. A Buddhist monk named Tamfing introduced papermaking to Japan in A.D. 610. Over the years the Japanese developed their own style for making paper the tame–zuki way, which has changed little. The papermaking mould (sugeta) is submerged in a pulp and water SLURRY and removed in one smooth upward movement. The papermaker immediately shakes the mould from side to side so that the slurry will distribute on the mould in an even layer. The sugeta is held still or propped on slats of wood while the water quickly drains. The screen (su) is then removed from the hinged frame (keta) and placed face down on a wet FELT or stack of newly made papers divided by felts. After pressing, the thick individual sheets are separated and dried. The nagashi–zuki method of paper- making is believed to have spread from Korea and developed in Japan around A.D. 800. A vegetable mucilage called NERI is an important ingredient in this process, controlling the even distribution of BAST FIBERS in the papermaking slurry and preventing the solution from draining too quickly through the su. The technique for making a sheet varies depending on the kind of paper, the thickness of the pulp solution, and the size of the paper. To form a typical sheet, the papermaker begins by plunging the mould at a forty–five–degree angle into a slurry. The papermaker then levels the submerged mould and draws it from the vat. As water slowly drains through the screen, the slurry is evenly and rhythmically tossed back and forth and from side to side, forming an even layer of fibers on the screen. The repeated dipping and tossing action causes the long bast fibers to cross and intertwine, strengthening the sheet in both directions. When the papermaker decides the sheet has been formed to the desired thickness, the process is completed with a tossing off of remaining liquid. The su is removed from the frame, and the sheet attached to it is laid down with slight pressure upon a pile of newly made sheets and given a gentle upward jerk to release one side of the sheet. The flexible su is then slowly peeled away, and the new sheet adheres to the stack of wet sheets. After pressing, the sheets are carefully separated and dried.

Jute An Indian BAST FIBER used for the manufacture of coarse sacking, bags, and string. Old sacking and bags are used as raw materials in papermaking.

Key Block The most essential PRINTING ELEMENT in a colour print, to which all other printing elements are registered.

Knife–cut Stencil A screen stencil made from a thin, transparent lacquer or synthetic resin-based layer laminated to a plastic sheet or wax paper. Areas of the layer that will be the image are cut away. The remaining layer on the plastic or paper support sheet is adhered to the mesh of the screen, and the support sheet is peeled away. Final touch–ups are made using BLOCKOUT COMPOUND, and the stencil is ready for printing.

Kozo A general term given to a variety of mulberry trees whose BAST FIBERS are used for papermaking. Kozo fibers are strong, sinewy, and very long. Paper made from this fiber is generally very strong and dimensionally stable.

Lampblack An oily, dull blue–black pigment used for making inks and paints produced by burning liquid hydrocarbons. From about 1400 lampblack was made by burning pitch resin or animal fat and collecting the soot on sheepskins or iron plates. The soot was scraped off and mixed with linseed oil to make a basic black ink or paint. Since the late 1800s lampblack has largely been superseded by carbon black produced commercially from the partial combustion of natural gas.

Laser–cut Woodblock A woodblock whose nonimage areas have been removed by burning with a carbon dioxide laser. The machine is driven by a computer equipped with an optical scanner that reads the drawing and programs the laser head to burn away the material around the image to a predetermined depth.

Letterpress A term broadly applied to all types of RELIEF PRINTING in which raised inked surfaces come in direct contact with the paper to transfer the impression or image. See also Platen Press; Vandercook Press.

Levigator A tool used to hand–grain lithography stones, made from a flat circular metal disk with a swivel handle mounted perpendicular to the outside edge. The disk is hand–rotated horizontally across the flat stone in a slurry of water and abrasive grit for GRAINING.

Lift Ground The only ETCHING technique in which it is possible to draw and print in positive. The drawing can be made with pen or brush. The process consists of drawing either on an aquatint ground or on a clean copper plate using a solution of sugar and India ink. After the solution is dry, the plate is thinly coated with an acid resist, dried, and immersed in a tray of warm water, which dissolves the sugar–ink mixture, lifting the resist coating off the plate. The exposed drawing is then etched and prepared for printing. Also called sugar lift.

Linecut A method of RELIEF PRINTING in which the nonimage areas are removed from the plate by such techniques as acid etching or cutting with tools.

Linocut A relief print cut in the same manner as a WOODCUT. The method became popular in the early 1910s but received serious attention only after Henri Matisse made linocut prints in the late 1930s followed by Pablo Picasso in 1939 and again in the late 1950s. The lino block consists of a thin layer of LINOLEUM mounted on wood. The soft linoleum can be cut in any direction without resistance and has a slightly textured surface that accepts ink evenly. Linoleum may be prepared and treated like an intaglio plate and etched with caustic soda (sodium hydroxide). Linoleum may also be surface–etched with the same acid to give it a rough texture.

Linoleum A material made from a composition of wood flour, oxidized linseed oil, gums, or other ingredients and colouring matter formed on a layer of burlap, canvas, or felt. Linoleum was patented in 1863 by an English rubber manufacturer Frederick Walton, as a floor or wall covering.

Linters The short fibers left behind in the ginning of cotton, too short to be spun into yarn, but useful for papermaking.

Litho Crayons and Pencils Drawing materials consisting of pigments, binders, and fatty substances, used to create the grease image on the PRINTING ELEMENT in LITHOGRAPHY. These materials are manufactured in varying degrees of hardness. They are also used in creating hand–drawn screenprint stencils.

Lithography The planographic printing process based on the antipathy of grease and water, invented in 1798 in Munich by Alois Senefelder. The PRINTING ELEMENTS used are slabs of Bavarian limestone or aluminum plates that are grained to varying degrees of roughness. Image areas can be created using pencils, crayons, tusche, or various grease, lacquer, or synthetic materials. as well as photochemical and transfer processes. After the stone or plate is drawn, a solution of GUM ARABIC and nitric acid is applied over the total surface, chemically producing water-receptive nonprinting areas and grease–receptive image areas. Once this procedure is carried out, the stone or plate must always be stored with a dried layer of gum arabic over its entire surface. Before printing, this gum film is washed off with water, and the printing element is kept continuously damp with water so that the ROLLER, which is charged with oil–base ink, can be rolled over the surface until the grease-receptive image area is sufficiently inked. Paper is laid directly on top of the inked stone or plate, which is then passed through a LITHOGRAPHY PRESS to print the image.

Lithography Press Modern hand lithography presses employ the same principle as the first lithography press, made in 1798 by Alois Senefelder. The lithography press has a movable horizontal BED that carries the PRINTING ELEMENT and a separate movable SCRAPER BAR assembly that applies pressure directly to the printing element. During printing, the stone or metal plate is inked on the press bed, and the paper is placed directly on top of the printing element with a TYMPAN over it. The bed is then moved into position under the scraper bar. This type of press forces ink uniformly into the surface of the papei creating a very sharp impression. The workshop uses a hydraulic lithography press developed by Kenneth Tyler in 1974 from his original 1965 design. The press uses hydraulic cylinders to drive the bed and scraper bar.

Lithotine A lithographic solvent developed by the Lithographic Technical Foundation in 1933 to replace turpentine. Lithotine is less toxic and irritating to the skin and is therefore less likely to cause dermatitis.

Litho Tusche A drawing medium manufactured in liquid and solid states, made from the same ingredients as LITHO CRAYONS AND PENCILS. Tusche can be diluted with water, LITHOTINE, or other solvents to produce a liquid medium for drawing on stone, aluminum plates, transfer paper, acetate, or Mylar. Tusche is also used in creating hand–drawn screenprint stencils. See also Wash Drawing.

Lost–Wax Process In foundry work, a system of casting whereby a wax master pattern is coated in a ceramic shell or other mold material and the wax is melted out of the mold (or “lost”) preparatory to pouring in molten metal to fill the space the wax occupied.

Makeready The steps taken to prepare a press for printing.

Masking Film A clear polyester support sheet, machine–coated with a transparent red film of strippable material that is knife–cut to make the design. Masking film can be used in any of the photochemical processes.

Masking Stencil The screen-printing term for the nonprinting areas of the screen, which are made by applying glue and water or lacquer-base fillers directly to the screen. See also Blockout; Knife-cut Stencil.

Mattoir A steel engraving tool shaped like a club with sharp points projecting from the head, set in a long, round wood handle. Used directly on metal or through a ground, like a ROCKER, to produce marks made up of small dots similar to chalk lines.

Mezzotint An INTAGLIO method in which the surface of a metal plate is uniformly incised, roughened, or textured with a spurlike tool called a ROCKER. This creates patterns of tone on the polished plate. Gradations from dark to light are produced by scraping and burnishing. Mezzotint is often combined with other intaglio methods. The mezzotint technique was invented by a German soldier, Ludwig von Siegen, in 1642.

Mitsumata A BAST FIBER derived from the shrub of the Thymelaeaceae family, used in papermaking. The fibers are fine–grained, soft, absorbent, and slightly lustrous.

Mixed-Media In printmaking, used to describe prints made by a combination of techniques, such as screen printing, LITHOGRAPHY, EMBOSSING, casting, or any other method of duplication, which can be combined with one another or with COLLAGE, hand–colouring, and stitching. Mixed–media prints can be editioned or made as one–of–a–kind impressions.

Mixed Pulp A PULP made by mixing two or more contrasting coloured pulps in the vat to create papers with a mottled effect.

Mold See Coloured, Pressed Paper Pulp; Cookie-Cutter Mold.

Monoprint A print that has been altered by colouring the paper before printing or by varying each impression during or after printing. A monoprint derives all or part of its image from PRINTING ELEMENTS, whereas in a MONOTYPE the image is painted directly onto a plate and then transferred to paper in a press. These prints are often hand–coloured and may include collage elements.

Monotype A unique image printed from a polished plate, glass, metal, or other material painted with ink. Although a monotype impression is generally one of a kind, a second, lighter impression from the painted PRINTING ELEMENT can be made. This process was invented in the 1640s by the Genoese etcher Giovanni Castiglione. See also Experimental Impression; Ghost Impression.

Mordant In INTAGLIO, a compound usually consisting of potassium chlorate, hydrochloric acid, and water, used for etching copper plates. This mixture is called Dutch mordant and is used more frequently than nitric mordant (nitric acid and water) or ferric chloride (iron perchloride) mordant. Ferric chloride is diluted with water, and for some formulas hydrochloric acid is added to the saturated liquid solution. In papermaking, a chemical agent used to fix dyes on FIBERS. One of the more common mordants is ALUM applied in conjunction with a dye.

Mould The basic instrument of paper-making, the carrier on which the sheet of paper is formed, consisting of a frame of wood or other material covered with a cloth, polyester, brass, or bronze screen and wire so as to exert a sievelike action when dipped into and raised from a vat containing a PULP and water mixture. FIBERS collect in a layer on the surface of the mould as water drains through. In a laid mould, individual wires are stretched or laid over the frame, leaving laid lines and “chain” lines where they are sewn to the mould, transferring their impression to the paper. A wove mould is covered with a woven wire cloth or screen or a polyester screen, and the paper made on it has a clean, unlined surface and FORMATION. See also Deckle; Japanese Papermaking; Su; Watermark.

Mould–made Paper A term for paper resembling handmade paper that is made on a CYLINDER MOULD MACHINE. It can be made with either a wove or laid finish and with a DECKLE EDGE. The machine forms a continuous sheet, which is passed between rollers to squeeze out the water. The sheet is then pressed against steam–heated cylinders and dried. Once dry, the sheet is either wound into a roll or, if mechanically marked for deckle edges, torn by hand with a wooden or bone slitter blade.

Multiple–Inking Technique One of various methods for depositing several colours on a PRINTING ELEMENT for simultaneous printing that have been developed for INTAGLIO and RELIEF PRINTING. Fingers, pieces of rolled felt or cloth, brushes, and BRAYERS are used to apply the colours to the plate.

Natural coloured A term applied to papers whose colour results from the natural materials they are made from, with little or no colouring matter added. Many Oriental papers are termed natural coloured.

Negative A image in which the black-and- white relationship of the original copy is reversed, as distinguished from a POSITIVE, in which the relationship is retained. In photographic processes this term is used to describe the exposed film made with a camera from which a positive print is made on photographic paper. A negative can be handmade with a brush using an opaque liquid or can be made from knife–cut film. See also Positive and Negative.

Neri A vegetable mucilage used in JAPANESE PAPERMAKING as a formation aid which allows the fibers to float evenly in the vat and controls the rate at which water filters through the screen. Neri also permits sheets to be stacked and later separated without the use of felts. Neri is manufactured from the root of the tororo–aoi plant or the inner bark of the nori–utsugi tree.

Offset Lithography An indirect printing process in which the inked image on the stone or plate is transferred to a cylindrical BLANKET, which then transfers the inked image to the paper. See also Indirect Printing Press.

Open Bite An intaglio plate on which no ground is used. A bold image is usually chosen for this technique. The drawing is made with a resist, and the plate is deeply bitten. During inking, the broad, open areas have a tendency to wipe clean, with ink holding on to only the sloped edges, imparting a hollow look to the printed shape. Open bite is to be distinguished from FOUL BITING.

Overprinting A shop term for printing colour or varnish over an existing printing. Also, in LITHOGRAPHY, a platemaking method in which a second NEGATIVE is exposed on an area of the plate previously exposed to a different negative; for example, combining line and halftone images on the same plate.

Paintstik A drawing stick made from oil paint, linseed oil, and solid additives to increase stiffness. Paintstiks can be mixed with turpentine or petroleum solvents. They are a favorite material for use in colouring prints and drawing images on PRINTING ELEMENTS. Paintstiks are trademarked products.

Palette A workshop term used to describe the range of colours used by an artist in a specific work.

Papermaking See Japanese Papermaking; Western Papermaking.

Paper Pressing The workshop term for the application of a fixed amount of pressure on a sheet of newly made paper in a PLATEN PRESS.

Paper Stencil A stencil made by sticking cut or torn pieces of paper to the screen to create nonprinting areas.

Papier-mâché Generally paper that has been repulped and mixed with a binder such as glue and is formed into a given shape by hand, by pressing. into a mold, or by stamping with a die.

Pattern Pistol A specially designed air gun used for spraying PULP. The gun, powered by an air compressor, has a large orifice and an attached pulp tank for spraying short pulp fibers. With this device thin layers of pulp can be sprayed onto a variety of surfaces, such as shaped molds and cloth.

pH A measure of the acidity or alkalinity of a solution as indicated on the pH scale from 0 to 14. A pH value of 7 is considered neutral, while solutions of a lower pH value are termed acidic and those of a high pH value are alkaline. The degree of acidity or alkalinity present in a solution is determined by its hydrogen ion content, which can be measured by various electronic and colour metric devices.

Photoengraving A process for making metal relief plates by using acid to etch a photographically produced image on the metal.

Photoetching See Photosensitive Resist Intaglio Plate.

Photographic Plate/Screen Making A shop term used to describe the process in which various types of film elements are assembled on a base sheet and placed in a VACUUM CONTACT FRAME with a sensitized plate or screen and exposed.

Photolithography on Stone A photochemical process based on the light–sensitive properties of bichromated albumin, invented in 1855 by Alphonse Louis Poitevin. However, the first successful photolithographic process was based on a bitumen process developed in Paris by the optician Lerebours and the lithographer Lemercier in 1852. The process was abandoned in favor of Poitevin’s because only a limited number of proofs could be pulled. Another early investigator of bichromates was the English inventor William Henry Fox Talbot, who in 1852 discovered the light sensitivity of a mixture of potassium bichromate and gelatin. He first used his patented process for the production of photographic etchings on steel. To make a photolitho stone, a grained stone is prepared, exposed, and processed using the same technique developed for the WIPE–ON ALUMINUM PLATE. The artwork contacted to the negative–type coating can be hand–drawn or photomechanically made. Photo–lithography on stone cannot produce results as uniform as wipe–on plates and therefore is rarely used. The one advantage, however, is that additional artwork can be added with dependability and ease, which is not the case with wipe–on plates. See also Screenless Lithography.

Photomechanical A generic term for any reproduction process in which photography is employed in the making of a printing surface. The term embraces photolithography, photoengraving, photostencil, and photorelief printmaking.

Photosensitive-Resist lntaglio Plate A relief plate made by a photochemical etching process in which a polished plate is hand-coated with either a negative–working or positive–working photoresist. In this technique a photoresist is applied to the plate, artwork is contacted to the plate and exposed in a VACUUM CONTACT FRAME, the resist is chemically processed to form a stencil, and the plate is etched in a tray of acid. Finally the plate surface is cleaned of all coating and prepared for additional image work or printing.

Photosensitive-Resist Magnesium Plate A relief plate made by a photochemical etching process in which a polished plate has a negative–working light-sensitized resist coating applied by hand. The coating is made of polyvinyl alcohol (PVA) sensitized with a dichromate. The artwork is contacted directly to the plate’s surface in a VACUUM CONTACT FRAME and exposed. The plate is developed by a spray of water, hardened with a chromic acid solution, heat-dried, and then processed into a relief element using the POWDERLESS ETCHING method. This type of plate can be printed in the same manner as a DIRECT–RESIST MAGNESIUM PLATE.

Plate A general shop term used to describe any type of PRINTING ELEMENT, such as a lithography plate or stone; a copper, zinc, or magnesium plate; or a woodblock.

Plate Mark The imprint made by the surface and beveled outer edges of a PRINTING ELEMENT when it is impressed into paper during printing. A stronger plate mark is visible when the paper is damp, as it often is in INTAGLIO printing.

Platen Press A hydraulic machine constructed with two identically shaped horizontal BEDS. Two platen presses were custom-made for the workshop; one with a movable top bed, the other with a movable bottom bed. One bed is permanently fixed, and the other bed, power driven, moves in a vertical direction. The bottom printing bed has a movable tray that is extended during preparation of the PRINTING ELEMENT and retracted for printing. The print impression is created when the two beds are pressed together, with printing element and material to be printed placed between them. Pressure is measured by pounds per square inch (PSI) on a calibrated gauge. Printing pressures can be set at a few pounds for very light impressions or at a hundred thousand pounds or more for very heavy impressions.

Plate Tone Tone created in an intaglio print by deliberately leaving a film of ink on the plate in the wiping. Plates can be selectively wiped to add tone to parts of the image.

Pochoir A direct method for hand-colouring prints with paints, inks, crayons, or pastels applied through a stencil. A brush, DABBER, or spray can or gun can be used to apply paints. The stencil material is usually knife–cut from thin coated paper, paperboard, plastic, or metal. Designs can also be chemically etched in thin metal to make the stencil. See also Stenciling.

Positive An image in which the black parts of black–and–white copy appear as black opaque areas on a transparent base or film, as distinguished from a NEGATIVE, which reverses the relationship. In photography, a camera–prepared image, generally on acetate, vinyl, or other plastic transparent material. A positive can be handmade using a brush and opaque liquid or made from knife–cut film.

Positive and Negative In printmaking, the image area is termed a positive and the background area a negative. In photography, positive and negative refer to light value; i.e., whether light and dark areas appear in the image as in the original (a positive image), or reversed (a negative image). A photograph is a POSITIVE, and the black–and–white camera negative of the photograph is a NEGATIVE.

Post The pile of wet newly made sheets of paper couched between felts and ready for pressing.

Powderless Etching The commercial process developed for mechanically etching magnesium, copper, and zinc relief plates. The process involves adding banking materials to the ACID BATH to form a film on the shoulders of the image areas to prevent undercutting as the metal is etched deeper. These proprietary additives are complex organic compounds formulated for use in specially designed etching machines. These machines are equipped with paddles that throw the etching solution onto the suspended plate. Etching solution contains the additives and 14% to 22% of 42° Baumé nitric acid by volume, and the bath is maintained at 85° to 130°F (30° to 54° C).

Prep Work A shop term describing preparations made for the artist in relation to image making. These include the selection or preparation of drawing materials, the grinding of stones, the preparation of Mylar or acetate films for drawing, and the setup for REGISTRATION.

Presensitized Continuous–Tone Aluminum Plate A newly developed type of lithography plate used by the workshop since 1980 for SCREENLESS LITHOGRAPHY.

Presensitized Plastic Relief Plate A relief plate made by a photochemical etching process that uses a negative-working, water–soluble photopolymer plate composed of a thick layer of photosensitive resins adhered to an aluminum backing. The negative (artwork) is contacted directly to the plate’s surface and exposed until light emitted through the negative hardens the image area resin all the way through to the base. After exposure the plate is washed out with water to remove all unexposed resin from the nonimage area, making a deep–recess plate.

Presensitized Plate A printing plate manufactured with a light–sensitive coating on its surface, ready for exposure and processing. The first generation of presensitized aluminum plates were manufactured in Germany by Kalle and Company, just prior to World War II. These coated plates are either additive or subtractive types: an additive–type plate requires the plate–maker to add image–reinforcing materials to the image areas during processing, and the coating on nonimage areas is either removed or rendered water–receptive during processing. With the subtractive–type plate, the image-reinforcing material is applied by the manufacturer, and during processing, the platemaker removes the unexposed coating from the background, simultaneously taking away the image–reinforcing material on the unexposed coating. Negative–type presensitized plates are made either as additive or subtractive plates. The processing steps for the additive plate are: (1) exposure through a NEGATIVE, (2) developing with an acidified gum solution to remove unexposed DIAZO coating and render the plate water–receptive, (3) application of lacquer emulsion to strengthen the image areas, (4) application of gum to the plate, and drying. In the processing of subtractive plates, exposure is also made through a negative, but for a longer period of time than required for the additive-type plate. A special developer removes the lacquer applied by the manufacturer during developing, which is followed by the application of a special gum solution that is rubbed smooth and completely dried. Positive-type presensitized plates are made so that the unexposed areas form the ink–receptive image. The processing steps are: (1) exposure through a POSITIVE, (2) developing with a special solution that removes all of the exposed sensitizer, (3) fixing with a solution that stops the action of the developer and renders the image insensitive to light, and (4) the application of gum to the plate.

Presentation Proof Occasionally an artist will dedicate an edition PROOF to a friend or collaborator. The dedication is usually inscribed on the front of the print in proximity to other signature information. It may include personal remarks, but it most often consists of a brief acknowledgment of the friend or collaborator. This proof is recorded as a special proof (SP).

Press A mechanical printing machine powered by hand or drive systems.

Print Documentation The permanent document prepared by the workshop and signed by both the artist and director to declare the information accurate. Included in this document are the number of impressions signed by the artist, dates of collaboration, print size, paper, medium, workshop print number, and a print description detailing printing elements and order, ink colours, collaborators’ names and role in production, and how and where the print was signed and chopped. Special notes about the edition are often included as well. See also Curating.

Printer’s Proof The print IMPRESSION(s) pulled for the printer(s) who collaborated with the artist and the workshop director in the creation and printing of an EDITION.

Printing Element Any material, such as a stone, screen, or metal plate, upon which a design is created for the purpose of making an impression. In prints involving more than one colour, a separate printing element is usually drawn for each colour. The exception is when a printing element has more than one colour applied to it and transfers these colours to the paper in one pass through the press.

Progressive Proofs Prints documenting the sequential printing pattern of an edition that involves the printing of two or more stones, plates, or screens. These proofs usually bear notations by the artist or printer. They are numbered with Arabic numerals and capital letters (e.g., 1A, 1B, 1C, 2A, 2B, etc.).

Proof A term generally applied to all individual impressions pulled prior to the printing of the published edition. These impressions are made to test the progress of the image for inking and printability on various papers. See also Colour Trial Proof; Trial Proof.

Pulp Reduced FIBERS that have been diluted with water and are ready to be formed into sheets of paper. Also called STUFF in the papermaking process.

Reference Proof An edition IMPRESSION, partially or completely printed, that is kept by the publisher and artist for reference. These proofs usually bear notations about printing and are chopped and dated. These proofs are not intended for sale or distribution and are not signed.

Registration The correct placement of one PRINTING ELEMENT with respect to another. Registration is both visually and mechanically assisted by the use of REGISTRATION MARKS, REGISTRATION NEEDLES, REGISTRATION PINS, and registration devices built into pressBEDS. Simple registration consists of tracing the image on the printing plate onto tracing paper to position the printed image on the paper using registration marks. An improvement on this method is to pull an impression that has registration marks as part of the image from the printing plate on a transparent plastic sheet. The sheet is used to position the image being printed on paper. The most accurate method is to attach registration pins to the printing element to align the printing paper, which is punched to fit the pins.

Registration Marks A mark in the form of cross lines, a dot, a short line, or a T shape. These marks are placed on the printing paper and the PRINTING ELEMENT to facilitate visual registration by hand. In screen printing, the marks are on the printing table. A common shop practice is to produce registration marks by hand-ruling, cutting, scribing, or scratching. These marks will vary in size, thickness, and position and can be used only when accurate registration is not required. For accurate registration, commercial registration marks are available in a variety of configurations such as targets and cross lines. Registration marks permit the alignment of the artwork and the printing element with the printing paper. During hand printing, the marked paper is laid to the registration marks on the printing element. For large prints two registration marks are placed inside the paper margin on opposite ends of the back sides of the paper, and REGISTRATION NEEDLES are pushed through the paper marks and aligned with the marks on the printing element. The paper is then guided into position on the printing element, and the registration needles are removed.

Registration Needle Any handcrafted device consisting of a thin needle or wire attached to a wooden handle used for registering paper and PRINTING ELEMENT.

Registration Pins A registration system that consists of a three–hole punch with matching pins attached to flat tabs that fit into the material that is punched. By punching and pinning film, overlay sheets, plates, and paper, printers can maintain accurate registration of these materials. The pins can also be taped on surfaces such as stones and press BEDS. Adjustments inregistration can be made simply by moving the pins.

Relief Printing A printing process in which the impression is created by the uncarved areas or the unprepared surface of the PRINTING ELEMENT, which has been inked with a ROLLER, BRAYER, or other tool. The cut, or incised, areas do not usually print, since they are recessed and are rarely inked. Nonetheless, during a run paper is often pushed into these sunken areas, creating an embossed effect. The recessed areas do print when the printing element is inked in the same manner as an etching plate, with the surface wiped clean, leaving ink in the recesses. WOODCUT and LINOCUT are usually used for relief printing.

Repoussage A technique for forcing up low sections of a printing plate. This is done by hammering in the area from the back of the plate. Metal or paper shims can be adhered to the back of the plate, which is then run through a press under heavy pressure to push tip the low sections to their original level.

Right to Print The IMPRESSION that meets the aesthetic and technical standards of the artist and workshop director. The approved print is the standard for the EDITION printing. The French call this the bon à tirer.

Rocker A wide, curved, multitoothed steel CHISEL mounted in a wooden handle, used to cut regular indentations into the metal plate for MEZZOTINT. By rocking in a set pattern, the teeth roughen the surface of the plate to produce the characteristic BURR of mezzotint.

Roller A tool used for applying ink and grounds, cylindrical in shape, with one handle on each end or fitted in a holder with a single handle. Leather rollers have a solid wooden core wrapped in felt and covered with leather. COMPOSITION ROLLERS have a hollow metal core covered with rubber, gelatin, or plastic and are made in varying degrees of hardness. Rollers vary in diameter and length. See also Brayer.

Roulette A tool with a sharp raised and textured revolving wheel that is used to make lines or areas of dots in a metal plate or ground. Roulettes are made in various sizes.

Rubylith A trade name for ruby–coloured masking film laminated to a transparent backing sheet, used in preparing hand–cut photopositives and negatives.

Scraper A triangular steel tool, hollow on three sides and tapering to a point at one end, mounted in a wooden handle. Used to shave off areas of metal such as a BURR or a faulty etching mark. Special scrapers made with only one or two cutting edges are employed to lighten mezzotint and aquatint grounds.

Scraper Bar The leather–covered blade of the direct LITHOGRAPHY PRESS, which exerts pressure against the inked stone or plate. A scraper bar may also be made from a beveled plastic bar. See also Tympan.

Screenless Lithography A technique dating to 1855, when the French chemist and civil engineer Alphonse Louis Poitevin discovered the light–sensitive properties of bichromated gelatin and invented both the photolithography and collotype processes. After the invention of the halftone screen in the 1880s, screenless lithography was abandoned. Until the end of World War II, two kinds of photomechanically made plates were used in lithography: albumin plates and deep-etch plates. Presensitized plates appeared in the 1950s, and wipe–on plates appeared in the 1960s. By the mid-1960s research on screenless lithography had successfully developed in Europe to the stage where continuous-tone plates could be manufactured for use with positive film images. Researchers discovered that under certain conditions the combination of fine plate grain and the newly developed plate coatings produced a plate capable of holding nearly all of the tones from a continuous-tone POSITIVE. Commercial use of this plate has not flourished; today it is still in limited use, primarily because the continuous–tone printing plate technology is expensive and necessitates stringent quality control. Since the late 1960s artists and printers have been experimenting with these new plates, using photomechanical film and handmade positives made from thin translucent or transparent plastic sheets and a variety of drawing and painting materials. Screenless lithography has been incorrectly referred to as diazo plate lithography and Mylar lithography. See also Presensitized Continuous–Tone Aluminum Plate.

Screenprint A print made by a stencil technique using fabric (silk or synthetic) stretched tightly over a frame. The nonprinting areas on the fabric are blocked out by adhering a stencil. The image areas are open fabric through which ink or paint is forced with a SQUEEGEE. The screen frame is hinged to a table (usually a vacuum table). The material to be printed is placed on the table, the screen is placed on top, and with the squeegee, ink is applied through the screen openings directly to the paper. Unlike many of the other printing media, screen printing can be done on almost any material.

Series A group of related prints that differs from a SUITE in that the prints are not published or sold as a group.

Serigraph The name coined for SILK SCREEN prints in the late 1930s in the United States. Credit for the name and much of the new interest in the medium is attributed to Anthony Velonis, a painter and graphic designer. He was the leader of the federally sponsored art project for screen printing under the Works Project Administration (WPA). The art historian and print curator Carl Zigrosser adopted the new term in an attempt to distinguish artistic screen printing from commercial printing.

Setoff A shop term for an impression made on the back of a sheer of paper by the wet ink on the print below it. To register a newly drawn PRINTING ELEMENT to an existing one, the printing element is inked, and an impression is pulled, dusted with powdered red chalk, and set off onto the new printing element by running through the press.

Silk Screen A term originally used in the United Stares for screen printing. Since silk mesh has been almost completely replaced by synthetic mesh, the term is misleading and outdated. See also Serigraph.

Sizing Chemical agents added to paper during or after manufacture to provide water resistance; a hard, resistant surface; or a surface more receptive to ink or watercolour. In some craft techniques sizing may be applied during printing. Sizing materials applied during the papermaking process may be added to PULP (beater sizing or stock sizing) or may be applied in a bath to the finished sheet (tub sizing). Materials conventionally used for beater sizing are rosin and ALUM or synthetic substances. Those used for tub sizing are starch, gelatin, or glue. In modern usage synthetic sizing materials may be applied to the paper surface uniformly or selectively.

Slurry In papermaking, a water suspension of FIBERS and other insoluble materials (fillers, pigments) prepared in a VAT. See also Furnish; Stuff.

Soft Ground A nondrying ground that is applied with a ROLLER to a warm plate but remains soft after the plate has cooled. Soft ground will adhere to paper or any other material pressed into it, freeing the metal of the coating for etching once the paper or material has been removed. The ground is also used for direct drawing, and anything that comes to hand can be used for marking the surface; for example, chalk, wood sticks, ends of screwdrivers, brushes, paper stumps, and fingertips. Soft ground is often combined with other INTAGLIO techniques. This process was invented in the 1640s by the Genoese etcher Giovanni Castiglione. See also Etching Ground; Hard Ground.

Special Proof See Presentation Proof.

Spitbite Aquatint A direct INTAGLIO method of painting the aquatint ground of an etching plate with a strong acid. Pale to dark tones can be achieved by varying the time and strength of the acid application. To break the surface tension of the acid flowing onto the plate and control its direction, small amounts of saliva, ethylene glycol, or Kodak Photoflo solution can be used with the acid. Traditionally a clean brush washed with water was coated with saliva and then dipped in concentrated nitric acid and brushed onto the ground.

Squeegee In screen printing, a device used to pull the reservoir of ink smoothly across the surface of the screen, forcing it through the open areas of the screen stencil to leave an evenly printed image on the printing stock. The squeegee is constructed of a flexible blade made from rubber or synthetic plastic composition and set in a metal holder or wooden handle.

Staining The application of liquid colours to the surface of a newly couched sheet of paper. During the pressing of the paper, the colour matter may spread or bleed further into the surface fibers of the newly made sheet. Traditionally, colouring material is applied to the surface of dry paper, except in the making of marble paper. See also Western Papermaking.

Stamping Direct printing from any surface that can be inked, with the impression made by hand. Designs can be cast or cut from various materials and made into stamps. FOUND OBJECTS may be used in their original form or altered.

State Print A PROOF made to record progress during the proofing process. Any impression that shows the progress of work on a PRINTING ELEMENT, whether by the artist or the printer, may become a state print. In colour printing, a state print may derive some or all of its printing plates and colours from an editioned image; the printing plates or colours as well as the printing order can he altered. New printing elements can also be introduced, altering the image further.

Steel Facing An electrolytic process patented in 1857 in which an extremely thin layer of hard iron is applied to the surface of a copper plate. The process increases resistance to wear, especially of plates made in the DRYPOINT technique. Steel–faced plates must always be kept coated with ink or ASPHALTUM to prevent rust and corrosion. To avoid this problem, plates today are faced with nickel or chrome, which offer a harder, brighter, and more resistant surface.

Stenciling A process for hand–colouring through a sheet of material with a cutout design. The simplest type of stencils are knife–cut from thin coated paper or plastic. Stencil designs can also be made on wide–mesh screens or etched through thin metal. A variety of tools are used for applying colour to prints. See also Pochoir.

Stipple Engraving An INTAGLIO technique in which tone is created on the plate by numerous dots, flicks, or short strokes made with a stipple BURIN. The earliest method for this process was invented by the Venetian artist Giulio Campagnola around 1500. Stipple marks may be engraved directly on the metal or made through a ground before ETCHING. The plate can be inked and printed as a relief or as an etching plate.

Stuff Prepared paper pulp ready for use in the VAT. Depending on the degree of beating and its dilution, the paper stock may be referred to as half stuff, frst stuff, second stuff, etc. See also Furnish; Slurry.

Su In JAPANESE PAPERMAKING, the removable flexible screen of the MOULD, held rigid by a clamshell–style frame equipped with copper hinges and catches. The screen is made of finely split and beveled bamboo splints woven together with silk threads and wooden strips attached to both ends.

Substrate The layer of material that serves as a base for a two–dimensional work, such as paper in prints and drawings and board, paper panel, and canvas in painting.

Sugar Lift See Lift Ground.

Suite A set of prints related by common imagery or theme and often by technique. A suite of prints is usually published in a portfolio with a title page and a COLOPHON page.

Surface Tone In INTAGLIO, printed tone caused by faulty wiping of the plate. See also Plate Tone.

Tarlatan A starched cotton fabric of open mesh, used for wiping away excess ink from the surface of intaglio plates.

Transfer Paper Specially prepared coated paper that can receive an image in various drawing media for the purpose of transferring it to a litho plate, stone, or intaglio plate. With transfer paper it is not necessary to draw the image in reverse, as it is with a direct–drawn litho or intaglio PRINTING ELEMENT.

Trial Proof A print, usually a unique impression in a single colour such as black, pulled during proofing to document image changes. Notations regarding the quality of the printing or the image are often written on the print by the artist or printer. See also Proof.

Tusche See Litho Tusche.

Tusche Screen A stencil made by drawing an image directly on the screen fabric with tusche or crayon. The screen fabric is then evenly coated with glue and dried, and the drawn areas are WASHED OUT with solvent to open the mesh of the stencil.

Tympan The plastic sheet placed between the SCRAPER BAR and the paper laid on top of the PRINTING ELEMENT in a direct LITHOGRAPHY PRESS. The press is designed so that the scraper bar applies pressure directly through the tympan to the paper and printing element on the press BED below. The tympan is greased to ensure a smooth passage for the scraper bar.

Vacuum Contact Frame A mechanical device used for exposing prepared film, masking film, or images drawn on plastic sheets to sensitized plates or screens. The machine is constructed of two horizontal metal frames hinged together on one side; the fixed bottom one carries a flexible rubber sheet (called a BLANKET) and the movable top one, a sheet of flawless glass. The rubber blanket is connected to a vacuum pump by means of a rubber tube. When in use, the plate is laid, coated side up, on the blanket, and the prepared film is laid on the plate. The glass top is closed and locked to the base frame. The vacuum pump is activated, and the air is sucked from the compartment between the two frames. This creates a vacuum, and the flexible rubber blanket collapses against the glass, forcing the film and plate into close contact. A mercury vapor lamp emitting shortwave radiation exposes the sensitized film, plate, or screen.

Vacuum Forming A process for forming wet PULP into single or multiple flat or shaped papers using a specially designed vacuum table. Flat sheets are either formed by couching or by pouring pulp directly onto a thin polyester fabric laid on the vacuum table. Shaped pieces are made by laying newly made, partially pressed sheets over or by pouring pulp into a relief MOULD placed on the table. The table has a perforated top with a sealed chamber below connected to a vacuum pump and tank. Work on the table is covered with a flexible plastic sheet, and a compressor beneath the table draws air and water from the plastic-covered enclosure, creating a vacuum and compressing the pulp.

Vacuum Screen Press A screen-printing press consisting of a vacuum table for holding the paper during printing and a frame device hinged to the table for keeping the screen in position. The table is an airtight box with a grid of evenly spaced holes on the top surface. It is equipped with a vacuum pump, which is activated during printing to draw the paper flat against the bed, ensuring even contact by the SQUEEGEE.

Vandercook Press A motor-driven flatbed cylinder machine in which the printing surface is flat and the impression surface cylindrical. Paper is pressed against the inked relief PRINTING ELEMENT by the impression cylinder. The machine has a motorized inking system, an automatic-fed FRISKET, and a manually operated gripper device for delivery of paper to the printing element. However printing elements are often hand-inked for stronger effects.

Variant Proofs PROOFS that have been identically printed and then altered by some method to make them different from one another, or proofs that have been varied in edition printing to make them unique.

Vat The large container that holds the SLURRY for papermaking.

Verso The back of a sheet of paper.

Vinyl Paints A group of chemically inert, lightfast, opaque, mat-finish paints that are water soluble when wet and insoluble when dry. The base is an emulsion of high-grade polymers, microscopic particles separated from one another by water. When the water evaporates during drying, these particles are fused with the pigments that were mixed with them. Since vinyl paints are an emulsion, it is possible to introduce a wide variety of materials, such as sand, glitter, or pulp, into the colours. The workshop began using vinyl paints to colour paper pulp in 1975.

Viscosity Printing An INTAGLIO method based on the principle that inks of different viscosities applied on a plate with a multilevel surface do not mix when printed in one pass through the press. In this method the design is bitten into the plate in two or three levels. With three-level plates the lowest level is wiped with stiff intaglio ink, and the middle and top levels are inked with rollers carrying inks of different viscosities (a hard roller is used for the thicker ink, a soft roller for the thinner ink). Two-level plates are generally inked with rollers only.

Wash Drawing In LITHOGRAPHY, a drawing made with diluted tusche (and sometimes with diluted ink). One of the most subtle of graphic techniques, giving the artist the freedom to draw spontaneously a wide range of continuous tones directly on the stone, aluminum plate, or TRANSFER PAPER. Preparation and printing of a wash drawing demand the highest skill of the printer. Even in the hands of the most experienced and gifted printer, there will always be slight losses and changes in the tone gradations. Stone produces the greatest range of tones. TRANSFER PAPER produces a harder and coarser effect than stone or aluminum plate. In the last ten years the workshop has perfected SCREENLESS LITHOGRAPHY so that wash drawings can be accurately and dependably produced. This technique has virtually replaced directly drawn stones and metal plate lithography. See also Continuous-Tone Film; Litho Tusche.

Washed Out A screen-printing term describing one of the steps in making a photographic screen stencil. After EXPOSURE in a VACUUM CONTACT FRAME, the unexposed light-sensitive coating on a screen or film is washed out with a fine spray of water. The exposed hardened coating remains to form the stencil image.

Washing Out A shop term for the removal of an image coating from a lithography plate or stone by use of LITHOTINE or other solvents.

Waterleaf The newly made wet sheet of any finished paper with no SIZING. Paper with a low degree of sizing is termed slack sized.

Watermark A design formed in fine wire or low-relief metal castings and sewn on the upper side of the papermaking MOULD. Since the design is in relief, less PULP lies on it than on the rest of the mould. The resulting thick and thin areas make the watermark slightly more translucent than the rest of the sheet. Watermarks are sometimes simulated by embossing or by printing with transparentizing oil or resin.

Western Papermaking The invention of paper by Ts’ai Lun in China around A.D. 105 slowly spread westward to the Arab world, arriving in Spain in the twelfth century. The hand papermaking process that developed in Europe subsequently has gone through little change, and this process is similar to the one used today at the workshop. The basic raw materials, cotton and linen rags or cotton LINTERS, used singly or in combination, are reduced to FIBERS in a BEATER. The fibers mixed with water are poured into a VAT, and a MOULD (wove or laid type) with DECKLE is dipped into the vat solution (SLURRY) in one continuous scooping action, made level several inches below the surface, pulled up smoothly out of the vat, and given a slight side-to-side shaking. The mould is held still for a few moments until the excess water drains through its surface, forming an even sheet of intertwined fibers. The deckle is removed, the mould is turned upside down, and the wet sheet is pressed onto a damp FELT using a rocking action (COUCHING). If more than one sheet is to he made, this procedure is repeated until a pile, or POST, has been made. The post is placed on a hydraulic press BED, and pressure is applied to squeeze out the excess water. After pressing, the compressed papers are separated sheet by sheet from the felts. The paper is then placed on screen trays or blotters for drying. coloured paper may he made by adding colouring matter to the vat or by applying dyes and COLOURED PULPS to the surface of newly made sheets before or after pressing.

Wipe-on Aluminum Plate A photolithography plate made by hand-wiping the surface of a commercially grained, anodized plate with either a negative- or positive- type DIAZO coating prior to use. Artwork is contacted directly to the plate, exposed, and developed.

Wire Side The side of a sheet of paper that is in contact with the wire (cover) of the MOULD, as distinguished from the felt, or top, side.

Wood Fiber Fiber derived from trees or woody plants and prepared by mechanical or chemical treatment.

Woodcut A method of RELIEF PRINTING in which wood is the PRINTING ELEMENT. A wide variety of cutting tools, power tools, or laser cutting machines are used to carve woodblocks. Woodcuts are the first known prints. The earliest woodcut prints and illustrations in existence were produced in China from Buddhist scriptures in A.D. 868. By the thirteenth century the process had reached Europe but was used only for textile printing. The earliest known wood- cuts printed on paper in the West date from the end of the fourteenth century.

Work Proof A PROOF that the artist has drawn, painted, or collaged on. This study is often used during proofing to indicate changes and becomes a reference for future printmaking.

Ken Tyler
Tyler Graphics Catalogue Raisonne 1974-1985
Walker Arts Center and Abbeville Press, New York 1987.