Polyester Plate lithography

Tiny prints of a Viking Funeral; image area 1.75″ square; embossed, bordered area about 2.125″ square

Thursday was day one of testing out printmaking without a press, and without toxic chemicals (the latter a bonus  for the artist and the environment). The last few supplies arrived Wednesday afternoon, so Kim and I embarked on some lo-fi printing yesterday, with rather hi-fi results (and much learned) for our first-run! It was also a lot of fun, and a satisfyingly physical art-making method.

The theory is simple enough but, as with most media, the technique takes “getting a feel” for the physics and chemistry– the way the materials interact. The premise upon which this method is based is simply ‘oil and water don’t mix’. Resistance. This entry outlines our approach, some of the things we learned, and links to the helpful sites where my research began.

Supplies:
Z-Acryl polyester plates;
Graphic Chemical roll-up black (oil-based litho) ink;
one glass palette;
one soft brayer;
a bottle of gum arabic;
a bottle of citric acid;
a bottle linseed oil;
printmaking paper (100% cotton rag Stonehenge, ruler-torn to size);
cheap plastic or glass bowl;
a clean pan or tub (for resting paper btw misting and blotting);
cellulose sponges;
a spray bottle;
clean newsprint; rags;
a clean towel
toothpaste (as a mild non-toxic abrasive cleanser

For gathering supplies, there are lots of places out there (Google), but I ordered my printmaking-specific bits from Blick. The citric acid (mine is liquid form so it’s ready-to-use) I ordered from Amazon (check Ebay, too). All the incidentals (rags, bowl, spray bottle, sponges etc) I acquired at a 99 cents store.

Tip: we used a large piece of thin plexiglass to cover our table to protect it; you could also use a plastic tablecloth or drop cloth, but the plexi was great as it stayed flat and smooth and was easy to clean up. If you’ve a worktable, this is not an issue but we were printing in my dining room!

Plate-making: We made our plates at Kim’s by laserprinting images of drawings onto the polyester sheets (plates), then ran them through a second time (by printing a blank page) to make sure of a good heat-fuse in the printer. A photocopier can be used if you haven’t a laerprinter. Wherever the toner has fused to the plate is where (theoretically) your ink will stick, too, leaving the untouched surface area clean– a basic form of positive imaging ink-transfer, much like an offset press. However in this more archaic method, the use of water (or more precisely, water with some help– see Inking) is paramount to its success.

Tip: Remember to flip your image horizontally in Photoshop (Image>Rotate Image> Flip Image Horizontally) before printing or you will get a reverse or mirror image when you print.

Tip: You may also employ direct plate-making by drawing onto the surface with ball point, sharpie, anything waterproof– then heat-treat for a few seconds in 180º oven.)

 

One of Kim’s prints, from an ink and wash drawing of Brooklyn buildings

 

Inking: The polyester plates have a faintly textured surface (don’t image on the smooth side). Prepare your ink by putting a small amount (maybe a teaspoon if your image is no larger than 8″ x 10″) onto your glass palette, than begin rolling out until it is a thin, even layer and makes just a slight hissing sound with rolling.

Prior to inking the plate you must wet the surface with a sponge.  Ideally you want to use a water mixture: in your cheap bow, put water (maybe 12 oz?), then add about a half ounce to an ounce of gum arabic and a teaspoon of citric acid. The gum arabic helps the water to “stay wet” on the plate, for lack of a better term, and the citric acid raises the Ph which helps to prevent “scumming” (that’s ink in places it shouldn’t be). Sponge a thin layer on, making sure the whole plate is evenly wet (you’ll see a lack of shine on dry spots- wet them!), then you roll your brayer over the surface of the plate; wipe again, repeat. After the initial ink-up (load it 5-6 times or more), we found about 3-4 inkings (always with water in between) worked quite nicely. However, we did experience rather a lot of “dot gain“, so next time we plan to thin the ink a little.

Tip: when ink gets where it shouldn’t, scrub with the same sponge and more water mixture to force it off, then re-wet the plate. If a LOT of ink gets where it shouldn’t, clean all the ink off with linseed, then clean that off with some toothpaste, water and your fingers, then rinse and start over!

Tip: do tests on newsprint during initial ink roll-ups to test, and use newsprint  to roll your brayer if it gets too “loaded”

 

Paper: Use your spray bottle (filled with water only) to mist the paper and let it sit for just a couple of minutes, then blot– we started with a towel, but there was lint, so switched to blotting on a towel, but between sheets of clean newsprint. We found this method resulted in the best impressions- you want it damp but not wet; just a bit softened up. (Ostensibly you need not wet the paper at all for this method, but with the textured surface of  printmaking paper it seems a good idea so the paper is more accepting.)

Tip: We tested and learned that bristol (hot pressed, smooth) took detail very nicely, but as it is not made to withstand the kind of soaking that printmaking papers can, one must take care to not over-mist– blot within a few minutes or the pulp will break down and stick to your plate!

 

A print from my pencil drawing, New Orleans Weather; the tonal  forms lost details as they darkened up, but this one on bristol held up decently.  (See original here)

 

Printing: We worked without a press (as I said, lo-fi), and hand-pulling prints by burnishing with a wooden spoon can lead to paper shift, over-working, or over-stretching of the paper– so be careful. Work the spoon from the center out to help reduce the blurring that can result. We actually first tried using only a baren, but the wooden spoon was more effective. For the smaller prints, we spooned than finished up with one good pressing of the baren.

Tip: When printing this way, try to stick with simpler, more linear images, OR print your image with a linescreen of perhaps 75 – 90 (though Z-Acryl states up to 133 lpi will work).  The semi-abstract, continuous tone images we started with (lots of tonal subtleties) gained density and lost detail over successive inkings, whereas the Viking image, with fewer tonal subtleties, with space between the linear wave elements (drawn after the style of an etching, go figure), held up more clearly. Personally I’m loathe to print with a visible linescreen, so I’d prefer to create imagery more suited to the material.

 

 

One missing element: One thing about this method I felt was lacking was that very satisfying hallmark of printmaking processes– the embossed edge that is the result of a (thicker) plate being pressed– these “plates” are far too thin to create such an edge. Though none of my research made note of this gaping aesthetic hole, I was determined to have it. We did a bit of experimentation: We mounted the plates (using YES! paste and a putty knife) to thin chipboard, trimmed to size; and carefully sealed the back with spray varnish (to keep it from breaking down with all the water), and let dry.
A happy side-effect of this was that it also kept the plate raised enough from the surface where we rolled our ink onto it, thereby allowing cleaner ink-roll-ups. You see, we had only a 6″ brayer, but had ganged up many images on the plate, which didn’t leave room for large enough margins for the brayer . Luckily our experiment worked, so it was a non-issue–  and it paid off in very pleasing ‘beveled’ impressions with inked borders. For longer-lasting results, next time we plan to mount the plates to plexi, as it will be far more waterproof and last through more impressions without falling apart (which our chipboard tests did after 10-12 impressions).

Tip: If you choose not to mount your plates, remember to leave enough extra plate material around your image to keep the inked brayer from touching your inking surface!

 

Clean Up: The oil-based ink cleans up easily with linseed oil, and once you’re down to nearly no ink, use toothpaste and water to do a final cleaning of your plate. Same method followed by soap and water for things like your bowl, glass palette, etc . This method is non-toxic, and the only real odor is that of the linseed oil, which is rather pleasant. It’s not terribly messy, but wear old clothes or an apron and keep lots of rags and newsprint on hand; paper towels also come in handy.

Research Many thanks to these helpful links:
Non-toxic printing; (super helpful and keeping it artist-friendly);
Mirka H how-to (with photos);
A YouTube demo so you can see it in action.
A How-to based on Kevin Haas’ PDF (very detailed and useful)