The traditional way involves copper plates, acids and delicate tissues, as well as a lot of space and studio equipment, but today we’re able to use an environmentally friendlier alternative, the photopolymer plate.
Unlike copper plates, these plates washout (develop) in plain water, are much easier to work with and are quicker to process. The polymer plate is twice exposed to uv light – once in contact with an aquatint screen (a stochastic, or random patterned screen producing a similar effect to a halftone) and then to the image positive. After both exposures and having removed the film, the plate is immersed in water and gently brushed with a soft sponge or brush for several minutes. This washout removes the unexposed and unhardened areas of polymer (shadows) while those that were exposed to uv light harden, become insoluble and remain on the plate (highlights). After processing the plate is dried and re-exposed to uv light to cure it and enable it to withstand the pressure of the press.
The plate is inked and gently wiped by hand using tarlatan to remove the ink from the lightest areas, but being careful to leave ink in the grooves of the darkest shadow areas. The finished plate is then placed on the bed of an intaglio press, covered with damp etching paper and the felts and run through the press. Under pressure the ink is squeezed out of the deep grooves and onto the paper to form the image. Carefully, the felts are lifted and the print pulled away from the plate and laid out to dry. The plate can then re-inked, wiped and printed until the edition is complete.
I teach workshops in the polymergravure process approximately twice a year, at the Minneapolis College of Art and Design and at Highpoint Center for Printmaking. To see the schedule, see the Workshops page.
Enchanted Forest — Alec Soth. Published and commissioned by Walker Art Center, 2010. Printed by Keith Taylor.