Intaglio
Intaglio prints are created by incising lines into a metal plate, historically copper, but more recently, zinc. After creating the lines, the plate is inked and then wiped clean to remove all excess ink from the surface, leaving only the ink inside the grooves of the lines. The printer lays a sheet of dampened paper over the plate and runs both through the press. The extreme pressure forces the paper into the lines where it picks up the ink, thus creating the image. Some different intaglio techniques include engraving, etching, mezzotint, aquatint, and drypoint. Each technique is printed the same but the way the lines are created on the plate is different.
For engraving, the oldest of the intaglio methods, the artist uses a tool called a burin, or graver, and creates the lines by incising directly into the plate.
Etching begins with an etcher covering the plate with an acid resistant ground material. Using an etching needle, the artist scratches lines into the ground material to expose the metal plate. When placed into an acid bath, only the exposed metal is “bitten” away. The longer the bite, the deeper the line will become, the more ink it will hold, and the darker it will print. The plate is then printed as described above.
To make a mezzotint, the artist works from dark to light, creating a tonal image. The entire surface of the plate is covered by densely overlapping indentations, using a tool called a rocker. The more indentations created on the plate, the more solidly black the plate will print. From there the artist takes a burnishing tool and smoothes away the sections of the plate that are intended to be areas of light. Mezzotints images are tonal rather than linear and were traditionally used to reproduce paintings.
Aquatint is also a tonal process of intaglio printing. Acid-resistant fine powder is dusted on areas of the plate where the image requires tonal effects. The acid then bites into the tiny intervals between the aquatint particles. When inked, the aquatinted areas create shaded passages. Artists often repeat this technique several times to create layered tonal effects. The artist may often combine aquatint with another technique to make an image both with tonal areas and with lines from another process.
Drypoint is similar to the engraving process in that lines are incised directly into the plate. The artist uses a tool called a drypoint needle. When the needle is pushed through the metal plate, it leaves raised metal edges called the “burr.” An engraver sands away the burr for a clean line. But for a drypoint, the burr is left on the plate. When the plate is inked and wiped, extra ink remains in the burr, creating a dark, velvety texture. Many fewer impressions can be pulled from a drypoint plate since the burr wears down more quickly than the rest of the plate under the pressure of the printing press.
The Converter at Night shows a steel mill in Pittsburgh in the early 1930s. Here, the monumental Bessemer Converter turns iron into steel in a process made even more dramatic in a night scene. Boyer created this drypoint on a treated aluminum plate, instead of the more common copper or zinc. She began experimenting with aluminum plates after Alcoa opened a Pittsburgh mill in 1931. Boyer was born and raised in Pittsburgh along the Monongahela River. Many of her works depict the laborers and mills along the riverside and explore the social and environmental impact of industry. The two diagonal lines seen on the top right and bottom left of the plate are cancellation marks, made by the artist or printer when the edition was complete; these marks prevent additional, unauthorized impressions from being pulled from the plate.