Vitreography technique

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A vitreograph is a print from a glass matrix. These hand-pulled prints are achieved through intaglio or planographic processes. Developed by glass artist Harvey K. Littleton in 1974, vitreography has been the focus of creative and technical efforts at Littleton Studios in Spruce Pine, North Carolina since 1981. Float glass plates, commonly used for windows or shelving, are run through an etching press for both the intaglio and planographic prints. Judith O'Rourke, long-time master printer at Littleton Studios, has successfully used ¼" think float glass for plates 16 x 20" or smaller; ⅜" thick float is required for larger plates.

Glass is an excellent material under compression which, combined with its near perfect elasticity, results in no degradation of the image under pressure. Glass plates are inert to the chemicals in inks, resulting in brilliant color that is free of oxidation contamination. Vitreography uses inexpensive, readily available materials and is a relatively non-toxic form of printmaking.

Before beginning to handle the glass plate, be sure that its edges have been seamed. A "seamed" edge is one that has been lightly sanded to remove sharp burrs. Glass with a seamed edge is safe to handle. A sanding block will take the sharpness off the edges of the glass plate, if you wish to do it yourself. Commercial glass vendors will seam glass that has been purchased from them for you, sometimes at no extra charge.]

How to create an intaglio vitreograph print: The following tips are excerpted from Ken Kerslake's article, "Vitreography," that was published in Printmaking Today, Vol. 3, No. 3, 1994. (The remarks in brackets [ ] were added by me to clarify Mr. Kerslake's descriptions of the process - Ellen Fischer).

Many techniques have been compiled at the Littleton Studios which offer the artist great latitude - some a direct carry over from the metal plate and some quite different. A diamond point needle or bit in a flexible shaft drill produces lines similar to dry point or engraving. Sand blasting, on the other hand, replaces acids and requires a different set of resists. Maskoid, hot glue guns and heavy grease crayons will resist sandblasting and the blaster hose itself, fitted with small points, can be used like an airbrush. For larger areas stencils can be cut from plastic adhesive paper.

Of all the stencil or drawing block-outs developed at this studio, one of the most interesting and versatile is white lithographic ink. Using this material, a great variety of tones and textures, quite painterly in character, can be developed.

[The white lithographic ink is applied with a brush or other instrument to the plate to develop imagery. It helps to lay the glass plate on top of a black piece of paper when painting with the white ink. Places where the plate is left bare will sandblast heavily, and thereby carry the most ink in printing the plate. Where the white ink is applied heavily it will resist the sandblasting most effectively; those areas will not be etched and will not carry ink. Areas in which the depth of the ink varies will be affected to greater or lesser degree by sandblasting, and will carry ink accordingly. The plate with its imagery in white litho ink must be sandblasted while the ink is still wet.]

It is usu

ally a good idea to check the image on a light table before sandblasting to determine the densities of the ink c

oating. Ink may also be rolled on the plate thickly and drawn through with sticks or wiped out with rags and solvents to create a subtractive image. It offers great flexibility and beautiful painterly effects.

At left: David Dodge Lewis's "Gouge Cemetery," an example of a print whose imagery was created on the plate with white litho ink. At left, an example of the technique by Thomas Buechner, "Erda Warns Wotan." Clicking on the links will take you to the artists' pages on this site.

Setting the image into the plate - sandblasting and frosting: The normal pressure used for blasting at the Littleton Studios is 60 pounds (US). Holding a nozzle well back from [the] plate, apply a light coating of silica [sand]. This is particularly important if the resist is a soft wet material, i.e., white litho ink because it is the combination of the ink and the coating of sand that creates the resist. Moving the nozzle closer to the plate continue blasting until [the] resist begins to disintegrate. Stop periodically to check the plate. Coarse sand mixtures will produce a quality similar to a coarse aquatint while fine Carborundum grains will have the effect of a box aquatint. (The plate must be thoroughly cleaned on both sides before inking it for the etching press.

Subtler tones can be made by etching or frosting the glass with [glass etching solution. It is found under different brand names at craft stores.] In contact with glass this rather gritty liquid will produce a 2% hydrofluoric acid solution that can be brushed on the plate m

much like a watercolor. The resulting tonal range is from light to medium gray. Some control can be had by diluting the Jack Frost with water or by the amount of time, up to 3 minutes, that it is left on the plate. After that time it loses much of its potency. . . Safety precautions must be taken with this material but the lovely wash effects are a distinct contrast to sandblasting and make it worth the effort. Both silica sand and hydrofluoric acid are hazardous materials and should only be used in well ventilated places with heavy rubber gloves and a good fume mask. Finally, clean the plate with mineral spirits followed by a 1"1 vinegar water solution to remove greasy residues.

At right: Untitled intaglio vitreograph by Bill Bernstein. Its gray tones were etched into the glass plate with Jack Frost.

Preparing the press: To avoid cracking the glass [plate] the press bed must be extremely smooth and clean. You can ascertain this by feeling the entire bed with your fingertips and removing any bur with [a] small flat file. Polish the bed with fine steel wool [and car rubbing compound. Finally, spray the entire bed with silicone spray and buff down with a soft rag.]

An interesting innovation at the Littleton Studios is the press templates which hold the plate in place and serve as convenient color registration forms. [It also prevents the roller on the press from catching on, and shattering, the glass edge. While a separate template must be made for each size plate, they are relatively easy to prepare. Cut two pieces of tempered masonite [hardboard], one 1/4 inch and one 1/8 inch to equal [the thickness of the glass plate, which is 3/8 inch thick. Make the tempered hardboard templates] wider than the paper normally used and about 12 inches longer. [Glue the two pieces of tempered hardboard] together with contact cement and cut a window in the center about 1/8 inch larger that the plate. [According to Jusdith O' Rourke, the best way to seal the hardboard template to protect it from moisture and inks is to adhere a piece of clear contact paper to the top surface of the template.] Place the template on the press bed and lock it under the press roller along with the printing blankets.

Above: Master Printer Judith O'Rourke pulling a print. The glass plate can be seen on the press bed. It rests inside a hardboard board template that keeps the margins of the paper level with the printing surface. Photo courtesy of Clarence Morgan.

Inking the intaglio the plate: Clean the glass plate thoroughly with mineral spirits followed by a 1:1 vinegar and water solution. Ink and wipe the plate as you would for any intaglio. Glass plates hold very little film and the finishing wipe may ne accomplished with tissue [paper] to remove all ink film if that is desired. Check the press bed in the [hardboard] template window for dirt or grit by holding your hand flat and feeling every square inch of the bed.

The next step is...critically important; stand the plate on its side with the back facing you. With the hand held flat feel the back of the plate. When you are certain the back is immaculate take it to the press bed. Slide the plate into the template window [and], pressing down with your fingers, move the plate back and forth listening for gritty sounds. If a sound is heard, repeat the cleaning process. When you are satisfied that everything is right, push the plate into one corner of the [hardboard template] and drop it into the window. A shim made of balsa wood trimmed to the thickness of the template will hold the [glass] plate tightly in place if you [wish]. Lay paper and print. When printing color plates...leave the paper firmly locked under the press roller while changing plates.

When the printing session is complete, clean the plate well with mineral spirits and vinegar water to remove all ink. This is important, particularly with sand blasted plates. Where the sand hits the plate it produces a tiny pit. Below the pit even smaller cracks occur. Ink penetrating into these cracks will, if allowed to dry, cause the plate to produce lighter impressions in subsequent printing.

How to create a vitreograph using the process of siligraphy: The following instructions were gleaned from several sources: www.baschwar.com/printmakers/Vitreography111499/index.html (Accessed 10/30/09), Veda Ozelle's "A Brief Guide to Siligraphy" from the book Hot Off the Press: Prints and Politics, (edited by Linda Tyler and Barry Walker, University of New Mexico, 1994) and the transcript of a workshop presented by Littleton Studios' master printer Judith O'Rourke.

Preparing the glass plate: The 3/8 inch float glass plate should be seamed (see above) for safety. One side of the plate must be grained (ground) by hand in a manner similar to a litho stone. Mark Mahaffey uses 100 grit carborundum and a steel levigator. Judith O'Rourke recommends 220 grit; she thinks it gives the plate a predictably fine textured drawing surface. If you don't have a levigator, Judith recommends grinding one glass plate on top of another with some carborundum sprinkled in between them. If you have never grained a litho stone, please do some research. As with graining a litho stone, graining a glass plate requires a large sink, a raised wooden platform to lay the plate flat on and water to lubricate the graining process.

After graining, the side of the glass that will hold the imagery should look evenly frosted. Rinse the plate well and dry it, and then wipe the surface of the plate with 90% isopropyl alcohol to sensitize it.

Note: Float glass siligraphy plates can be reused. Processed imagery can be removed by graining, after which the plate is resensitized with 90% isopropyl alcohol.

As an alternative to using a glass plate, Mark Mahaffey recommends a sheet of frosted Mylar attached with spray adhesive (frosted side up) to a heavy piece of compressed cardboard or other smooth surface (say, a piece of seamed 3/8 inch glass!). If using cardboard or another type of absorbent backing, the Mylar must be attached to it after the image is drawn and processed. The backing should be slightly larger than the Mylar.

Creating the image: Using either the 3/8 inch float glass plate or the frosted Mylar, draw your image with any black, water-soluble medium. Judith O'Rourke recommends water-soluble black pencils made by Omnichrome, Stabilo, Mars Staedler. Water soluble paints can also be applied to the plate. Any type of commercially prepared, black powdered tempera paint mixed with distilled water works well, according to Judith. Anything that is water soluble can be used to make a mark on the plate, including India ink, black watercolor and black gouache. Mixed with Kodak Photo-Flo solution, these materials will render reticulated wash effects, according to Mark Mahaff

ey. Judith obtains a reticulated tusche wash by mixing tempera paint with distilled water and slivers of Ivory bar soap. Veda Ozelle in ""A Brief Guide to Siligraphy" strongly recommends heat-curing plates on which tempe

ra has been used to better adhere the tempera to the plate. This can be accomplished by drying tempera washes with a hair drier.

Futura Floor Finish creates a nice, solid flat black, according to Judith. Gum arabic also gives rich blacks and can be applied with a pen and nib or sprayed on with an airbrush. Slight dilution with water will make the gum arabic flow more easily. Be aware of inadvertent mark-making on the plate. Even the spray from a sneeze will attract ink after the plate is processed. For this reason, don't blow crumbs of drawing material from the surface of a plate; use a soft brush to gently sweep them away.

At left: William Kitchens's "High Chair" was drawn on the plate with a water-soluble pencil. At right: "Bananas and Kiwis" by Ellen Fischer incorporates reticulated washes.

Note: Unlike a metal plate or a litho stone, you can't scrape, burnish out or otherwise delete marks on the glass plate. What you put down is there to stay.

Processing the image: Make a 50/50 mixture of 100% clear silicone sealant and synthetic turpentine, which is sold under the trade name of T.R.P.S. Judith O'Rourke notes that any Any brand of 100% silicone sealant works well, just as long as it says “non-paintable” on the tube. The mixture should be the consistency of corn syrup. Mark Mahaffey uses a foam brush to apply the silicone solution to the entire image support, whether it be a glass plate or a Mylar sheet. Wipe the surface with a Kim Wipe, buffing it down just as you would do with gum arabic on a litho stone. Coat the plate only once with the mixture, and then let it cure overnight. Mark advises a curing period of eight hours, and says that if you are using a glass plate, you can put it into a 150° oven for 1½ hours to thoroughly cure the silicone surface.

After the silicone surface cures, place the glass (or Mylar) in a plastic tray or tub of warm (not hot) soap and water. Gently wipe the surface of the glass with a sponge until all of the drawing material is washed out. Blot off the excess water from the plate and allow it to thoroughly air dry, or use a hair drier on it. You may still see a light image on the plate even after the image is washed out, but the support should be fairly clear.

Inking the image: Mark Mahaffey recommends creating a matrix to go around the glass plate before inking it to prevent catching (and perhaps damaging) the roller on the edges of the glass. Make the matrix from strips of ⅜ inch acrylic sheet. Use packing tape to hold the strips together.

Mark recommends Daniel Smith 100 Black Lithography ink mixed with magnesium carbonate (mag/talc). The ink should be very stiff and short, he says. According to Veda Ozelle in "A Brief Guide to Siligraphy," Stiff Inks with low grease content are best suited for siligraphic printing.

Ink the plate up slowly with a lithography roller in many directions, usually one pass in each direction.

Printing the vitreograph: An etching press is used to print the plate. Before printing, set the press to the correct height for a ⅜ inch plate. As in printing an intaglio vitreograph, a ⅜ inch hardboard template should surround the plate. (Please see Preparing the press, above.)

To register more than one plate, use T and Bar registration. Make horizontal and vertical center lines on the hardboard template. Then make corresponding marks (bars) on the back of your printing paper.

At right: The siligraph "Close Encounter" by Jeff Sippel used multiple registered plates.

Use newsprint to take your first proof; remove the plate to your inking station and toll it up again. Take the second proof on newsprint. and proof once more on newsprint. Subsequent prints can be taken on good quality rag etching paper. Good paper can be printed dry or dampened.

Clean up: Judith O'Rourke uses cooking oil for cleaning ink from the plates because it is non-toxic and has no harmful fumes.