The process of polymer plate intaglio (also known as photopolymer intaglio, polymer photogravure or polymer-gravure) has it’s roots in the historical process of copper plate photogravure. This process began in 1829 with the experiments of Joseph Nicéphore Niépce. Using pewter plates coated with asphaltum, and exposing it to a waxed engraving, he was able to etch the plate to produce a printable plate. In 1833, William Talbot perfected the process, using a copper plate coated with gelatin treated with potassium bichromate that could be exposed with a paper positive to give an etched plate with a full tonal range. Photogravure went on to become the predominant method for the reproduction of photographic images in the 19th century. The first half of the 20th century saw the use of photogravure in Alfred Stieglitz's Camera Work and in the series by Edward Curtis on North American Indians, only to be replaced by faster and cheaper forms of reproduction.
In 1993 I trained with Dodie Warren in the copper plate photogravure technique, and went on to use the process for 16 years to print my own photographic images. In 2009, the only large scale producer of the gelatin tissue used in the photogravure process announced that they would cease production. At that point, with the help of fellow printer Jack Reisland, I made the switch to polymer plate intaglio.
Instead of the copper plate and light sensitive gelatin used in the traditional photogravure process, polymer plate intaglio utilizes a thin steel plate covered with a UV light sensitive polymer layer. This light-sensitive plate is covered with a transparent positive of the desired image and exposed to UV light in a special exposure unit.
The exposed plate is then carefully developed in water. The water dissolves and washes away the less-exposed polymer, leaving a plate that is filled with microscopic hills and valleys. The plate is then finally re-exposed to UV to harden the polymer the rest of the way. After trimming the edges, the plate is now ready for printing.
The plate is inked using the desired color of intaglio ink. I prefer to use Charbonnel inks for their consistently high quality and dense pigmentation. The plate is carefully wiped with a printmaker’s tarlatan, then gently hand-and-finger wiped to best bring out the details of the image.
The proper wiping of the plate takes years to learn in order to perfect the technique.
The plate is then placed on the bed of an intaglio etching press, and covered with the print paper. I use only acid-free mould-made cotton fiber papers made by Fabriano or by Magnani, both based in Italy. The paper has to be carefully dampened to the correct moisture content to accept the ink. The paper is then covered with special wool press blankets, and then the plate and paper is run through the etching press. This drives the paper down into the tiny valleys in the plate with 1,500 pounds of pressure per square inch, transferring all of the ink into the surface of the paper. The print is then removed from the press and put into a special drying rack to insure that it dries flat. Once the print is dry and inspected for quality, it is signed and numbered. The entire process of pulling a single print can take up to an hour.