Peter Miller	About Photogravure
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What's this? Basic introduction to photogravure. Last modified: 2003-02-21

About Photogravure

Reported by Philbert Ono

This 19th-century process was totally new to me. However, after completing a grand tour of Peter's modest workshop and darkroom at his home in Kamakura, Tokyo in 1997, I was able to grasp a better picture of this rare art form. (Few people in the world do the entire photogravure process.) He explained the entire process and the materials and equipment he used. I couldn't believe how intricate and delicate the whole thing was. Not to mention tedious and time-consuming. It took him years of trial and error to attain a reasonable success rate with photogravure printmaking. He is truly dedicated and a true artist.

The Photogravure Process
The way I see it, the process involves three basic stages: 1. Image making, 2. Copper-plate etching, and 3. Printing. Each stage, of course, requires a number of steps. A photograph is captured on black-and-white film with a large-format camera, the image is etched on a copper plate through a chemical process, and ink is spread on the plate and paper is pressed against the plate to make a print. Almost everything is done by hand and any number of things can go wrong during each stage. Exacting conditions of temperature, humidity, exposure, chemical purity and concentration, pressure, timing, and human skill are required. It takes a month for Peter to make a photogravure print. (He usually works on several plates at a time.)

1. Image making
It starts with capturing the image. Peter uses a large-format camera (usually 8x10 in.) to make black-and-white images. He always keeps in mind how the image would look as a photogravure print. The separation of adjacent tones is very important. He uses filters when necessary to help differentiate tones that the film would otherwise record as the same shade of gray. It can take him an entire to day to go through only 12 sheets of film. Quality over quantity, he says. He photographs temples in Kamakura (his home since 1990), seascapes, snow scenes, root plants like potatoes and taro, trees and brush, and pathways. You can see many of his prints at his Web site, The Kamakura Print Collection. His site also gives a more detailed description of photogravure printmaking.

2. Copper-plate etching
This stage is the most difficult and critical. First, a positive transparency is made from the black-and-white negative. This transparency is placed flat over a thin sheet of ultraviolet-sensitive gel. The transparency and gel come into perfect contact by a special vacuum frame under an ultraviolet light projector (see photo). The gel is exposed to the ultraviolet light through the transparency. The lighter areas of the transparency allow more ultraviolet light to pass through, and the darker areas allow less to pass through. When the gel is exposed to ultraviolet light, it hardens and becomes insoluble (in water). The more ultraviolet light it receives, the harder and more insoluble the gel becomes. Thus, the gel under the lighter areas of the transparency become very hard and insoluble.

The ultraviolet-exposed gel sheet is then transferred to a thin copper plate, an extremely delicate operation. It must be done quickly and there must not be any air bubbles trapped between the gel and copper plate. After the gel is allowed to set on the copper plate, warm water is used to wash off the soluble parts of the gel. The insoluble parts of the gel hardened by the ultraviolet light remain on the copper plate. When it dries, the thin film of gel becomes a semi-permeable resist on the copper plate. Under the gel, the copper plate surface has a thin layer of powdery grain called aquatint. This layer, heat-fused on the surface, enables the etched crevices in the copper plate to hold ink. It also gives the print a grainy appearance.

The copper plate is now ready for etching with ferric chloride etchant. This chemical permeates the semi-permeable resist and etches the copper plate. The etchant gets through the thinnest parts of the resist first, while the more hardened, thicker parts of the resist hold back the etchant longer so less of the copper plate is etched. The dark tones of the image thereby receive the deepest pits, while the lighter tones are etched less. Unlike woodcuts where the raised parts are inked and the crevices are empty of ink, photogravure plates work in the opposite way. The etched crevices hold the ink and the raised "lands" are almost devoid of ink. A proof is made with the newly-etched plate to check the etching. If the proof looks okay, the leftover resist and aquatint are removed and the plate becomes ready to serve its purpose.

3. Printing
Peter uses a variety of fine inks and papers for print making. There are warmer and cooler black inks and more absorbent and less absorbent papers. Japanese washi is also used. He chooses the ink and paper to suit the type of image or tone to be printed. Ink is applied to the copper plate with a roller. The ink is then wiped off several times with decreasing pressure so that ink remains in the etched crevices (shadows) and removed from the unetched surfaces (highlights). He then makes a final, light pass of the rag to apply a little ink on the highlights. This is to distinguish them from the pure white of the paper. The copper plate and paper then go through high-pressure rollers to make the impression (this is "the most exciting moment"). The print is then air-dried for a week to ten days. The finished print can look very beautiful with many subtle but distinct tones. (The images you see on the computer screen don't do them justice.)