22 July 2011


An old friend from graduate school recently purchased one of my prints and asked for more information on the process, so I wrote this big, long detailed thing. Then I realized it might make an interesting blog post. You can read Jade's comments on the print after she got it in the mail on her blog.

"Liminal" is an intaglio print (specifically line etching, drypoint and aquatint), hand-printed on cotton rag paper.

The process begins with coating a copper plate in hard ground (essentially a pigmented wax suspended in a solvent that dries to a relatively hard coating on the plate). Then I hand-drew the lines into the hard ground with an etching needle. The plate was etched in a solution called "Edinburgh etch" (ferric chloride and ascorbic acid, I think, though I'm not certain of the proportions). Some lines were filled in and the plate re-etched, and so on, creating deeper, darker lines where they were etched longest, and lighter lines elsewhere.

The aquatint was added second and begins by cleaning the plate of hard ground and grease and sprinkling it with finely ground resin, which is then adhered to the plate with heat. Then the plate is stopped out with hard ground so that only the exposed areas with be etched. As with the lines, the plate is again alternately etched and stopped out to create areas of different tone. The resin creates a fine dot pattern on the plate, which prints as tone--different amounts of etching give different tones.

Finally, I added the cross-hatching by directly scribing lines onto the plate with an etching needle in a technique called "drypoint." This creates a fuzzy look on the lines, where the ragged edges of scribed copper also retain ink.

Then the plate is cleaned again, and de-greased. Then etching ink--in this case a very dark brown--is spread over the entire surface. Then the plate is wiped using tarlatan (a stiff, loosely woven fabric something like heavily starched cheesecloth). The final wipe is done with small pieces of newsprint. This leaves the plate clean of ink where there is bare copper, but inked below the surface of the plate where there are lines or aquatint.

A variety of papers can be used for intaglio printing, but heavy cotton rag gives very good results. The rag paper is soaked and then blotted, so it is consistently damp. The plate goes on the bed of the press, then the paper, then some newsprint, then three layers of press blankets, and the whole sandwich is cranked through at high pressure. This forces the paper into the recessed lines of ink and creates the distinctive raised ink and embossed plate border seen in intaglio prints.

For reasons that probably made sense at the time, I didn't edition "Liminal" but only made a few unnumbered proofs. Then I re-worked the plate--mostly the background--and printed it again, this time as "Interstitial," of which I also made only a few proofs.

Much of the background was removed simply by stopping out the image area and letting the acid eat away the detail. This results in something called "openbite" with is usually a mistake, but can also be used as part of the design. It produces large featureless areas and a dark line of ink around any areas that were protected from the etch.

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