Non-toxic Polyester Plate Lithography
George F. Roberts, Emeritus Professor (Deceased)
Boise State University
Department of Art
1910 University Dr.
Boise, Idaho 83725
Copyright © 1997 George F. Roberts
POLYESTER PLATE LITHOGRAPHY
Pronto Plates, Omega E-Z Plates or polyester lithographic plates are designed to resemble the surface of aluminum lithographic plates and are used as offset lithographs. They are water loving and are simple to image either by hand or using digital imaging methods. The following are instructions on how they can be used as hand printed lithographs.
Toner Tusche
Traditional looking tusche drawing can be achieved on the polyester plates using a toner tusche . The toner tusche consists of two parts rubbing alcohol, one part water, one half part toner and one quarter part Hunt Speedball screen printing Drawing Fluid or pancake syrup. The function of the drawing fluid is to give the tusche enough stability to stay where it is brushed on the plates. If a less controlled mark is desired the drawing fluid can be left out. Brush the toner tusche on the plate or apply it with a drawing nib. Draw with the toner in thin layers or it will interfere with fusing and printing. As you draw, keep in mind that the toner prints a bit darker than the drawing looks on the plate. When the drawing is finished, let the plate dry. As it dries, the alcohol, water and drawing fluid will evaporate leaving only the toner.
Fusing the Toner to the Plate
When the toner tusche drawing is finished, fuse it to the plate by heating it in an oven at 250 degrees for four minutes. Preheat the oven with a cookie sheet inside. Place the polyester plate on the cookie sheet and watch the time carefully. Too much heat will warp and burn the plate. The distributors of Pronto Plates recommends the oven temperature be 190 degrees and the plate be heated for three minutes. Evidently all ovens do not heat the same. Pretest the oven heating temperature and time to insure proper fusing. The toner is fully fused to the plate when it won't wash off with water.
Making A Hot Plate Oven
A oven can be made using a hot plate. Since most print studios have hot plates it is simple to convert them to an oven. Using galvanized sheet metal that an inch or so longer than the hot plate make a simple oven top and sides by bending one half inches on two ends of the sheet. Place the bent metal on the hot plate so the open end faces the front. Using a slightly smaller piece of sheet metal bend two ends about one quarter inch on each end. This piece functions as the shelf on which the polyester plates are placed. Use a inexpensive oven thermometer to test the temperature. Between 190 and 220 degrees works well. The plates should be heated for between three and seven minutes in the hot plate oven.
Photolithography
Photographic images are put on polyester plates using digital imaging techniques. High resolution scanners, printers and high memory capacity computers will insure the greatest detail and accuracy. Once the photographic image is printed on the Polyester plate using a laser jet printer the plate is ready to print as a fine art lithograph. The toner is fused to the plate in the printer. Another method of putting photo images on the polyester plates is using a toner based copier. Run the polyester plate through the copier instead of paper. The better the copier the better the results. Besides using a laser jet printer, copier and the toner tusche below are drawing material that will image a polyester plate.
Permanent Marker
Drawing Materials
The following is a list of material that can be used to image a polyester plate.
1. Black ball point pen.
2. Permanent Marker.
3. China Marker
4. Stones Crayon
Ball Point Pen and China Marker
Draw with them as you would on paper. Be sure to push hard enough so they are in the pores of the plate and not just on top of them. Marks made by any of the above can be scratched through or erased with a pencil eraser.
Texture Techniques
5. Future Acrylic Floor Polish. Add india ink to the Future so it can be seen of the plate.
6. Hunt Speedball Screen Filler. Dilute it with water, three parts water to one part screen filler.
7. Carbon based, waterproof India ink.
8. Carbon black acrylic paint
Wash Techniques
All of these materials can be used in a variety of way. Paint them on
the plate or use a drawing nib. Stamp a texture on the plate using them,
or use a tooth brush to spatter the material on to the plate.
Use an airbrush to draw with them or brush them in to alcohol for odd effects.
Resists
A resist is a mask used to retain white areas. Gum Arabic, water soluble lithographic pencils andcrayons and rubber cement are good resist materials. With any of these put them on the plate priorto using any drawing material. When they are completely dry draw over the top of them. To remove the resist use water and a sponge rubbing lightly. The resist will come off lifting the drawing material on top of it. Those areas will remain white in the midst of the drawing.
Printing a Polyester Plate
A Polyester Plate is ready to print emidiately after the artist is finished working on it. No acid or Gum Arabic is necessary. No asphaltum rub up, talc, or rosin is needed to prepare the plate for etching because no etching is required. By eliminating these steps much of the toxic nature of the old lithography process is eliminated.
To print a lithograph the plate must be wet prior to rolling it with ink. The distributor of the Polyester Plates recommends that the pH of the dampening water should be between four and one half and five and one half for optimum printing. They make a fountain solution that can be added to the water which will insure the proper pH. For example, the pH of the water in Boise is seven, so eight teaspoons of fountain solution are added to a liter to balance the pH. The fountain solution will remove drawing materials from the plate so fountain solution should be used sparingly or not at all when printing drawings. A teaspoon of fountain solution in a liter of water will not erase the drawing.
Thin soft paper like Rives Heavy Weight can be printed dry. Heavier printing papers need to be dampened to print well. Soak the paper of spritz it with a spray bottle. In either case blot the paper before printing on it. The ink should be a standard lithographic ink. When the ink and paper are prepared, the polyester plate should be placed on a wet piece of glass . The water will cause the polyester plate to stick to the glass and not be picked up when the ink roller is passed over it. As an added precaution use cloths pens or spring clamps to hold the front edge of the plate to the glass. Once the plate is stuck to the glass, wet its surface using a cellulose sponge and the pH balanced water. Run the inked roller across the plate several times then rewet the plate. Re-ink and repeat the process again until the plate is properly inked. Inking a polyester plate is the same as inking a lithographic stone. As a rule of thumb, if the plate won't accept the ink use less or no fountain solution. If the plate scums or over inks too quickly use more fountain solution in the wetting water.
Intaglio Press
The Polyester plates can be printed by hand or on an intaglio or lithographic press. To print using an intaglio press remove the felts and adjust the pressure so the upper roller is contacting the press be. Place three sheets of newsprint on the press bed. Place the plate on top of the newsprint and the print paper on top of that. Run them all through the press.
Litho Press with Backing Paper
Lithograhic Press
Printing on a lithographic press is also simple. Since Polyester Plates are thin it is necessary to put a clean lithographic stone, aluminum plate backer or a formica laminated three quarter inch plywood on the press bed. Place backing paper on the plate backer. Put the plate on the paper followed by , the printing paper, newsprint and greased tympan. Print the plate as usual.
Printing by Hand
To print by hand, ink the plate and place it face down on top of printing paper. Work on a flat smooth surface to insure an accurate print. Using a wood spoon or any other kind of burnisher rub the back of the plate methodically to cause the ink to come off the plate and on to the paper. Check the printing periodically by lifting one corner of the plate.
Reworking the Print
One nice qcharacteristic of a Polyester Plate is that it can be reworked during printing. Additional drawing or deleting can occur while the ink is still on the plate. Add marks to the plate using any of the drawing materials. Remove unwanted tonal areas by scraping them away with a razor blade or by using fountain solution or a pencil eraser. Since no etching or Gum Arabic is involved it is not necessary to counter etch or retch the plate. Once the modifications are finished, printing can continue immediately.
Clean Up
Clean up is simple and solvent free. Vegetable oil, liquid detergent, fountain solution and rubbing alcohol are all that is necessary. Clean the ink off the roller and ink slab with a rag and vegetable oil. Clean the vegetable oil and ink residue off the ink roller using liquid detergent and water. The rubbing alcohol is used to finish cleaning the ink slab. To clean the plate, print it on newsprint three times without inking it. Now, clean it lightly with fountain solution and a sponge. If you are cleaning a drawing plate dilute the fountain solution with water so it won't remove the drawing.