How an Aquatint is Made

In printmaking, a process called etching employs a metal plate covered in a thick, inky substance called a ground, which resists acid. As the plate is heated, the ground melts and can be spread easily across the metal's surface. After the ground cools, the image is scratched into it with an etching tool. When the plate is immersed in the acid bath, the acid bites, or eats away, only those areas where the ground has been scratched away. The plate is then covered with ink and wiped down, leaving only the places that have been bitten filled with ink. When printed, only those areas scratched away translate as black on the paper. In etching, a special ground called aquatint is used to create continuous tones, rather than just contours and negative space. Aquatint ground is a resin powder that resists acid when it is sealed to the metal plate. The plate is put in a dust box filled with this powder. By turning a wheel inside the box, a dust-cloud is created; when the wheel is stopped the dust settles evenly onto the plate. To seal the powder to the metal, it must be heated from the underside of the plate. When the plate is immersed in the acid, it is bitten in tiny pools around each particle of powder, creating tiny depressions which retain the ink when wiped. Upon printing the effect of a soft grain is imparted. With black and white reproductions, many successive layers of aquatint resin can be applied between each biting, so as to produce subtle gradations of tone, in close imitation of washes of watercolor . For color prints, separate plates were often made for each color. This method, called multiple-plate printing, requires several plates, and several carefully registered printings on the same sheet of paper. Another method is called a la poupée, where separate areas of the plate are carefully filled in with different colors of ink, then printed once. Colored illustration for publication was sometimes made by individually hand coloring black and white engravings.

Emily Martin