Teresa DeWitt, age 17, of Chester, Pa., for her question:
CAN YOU EXPLAIN ETCHING?
Etching is the process in which a picture is placed on a smooth sheet of metal, usually copper, from which an impression is later to be transferred to paper. The picture that is produced by printing from the metal plate is called an etching.
An etcher covers one side of the copper plate with a thin coating of wax. Then with a tool that looks very much like a needle, the etcher draws a design in the wax, using the tool as if it were a pen. On the back of the plate the etcher applies a layer of varnish.
Next the etcher makes up a special bath of acid. And into this liquid, the etcher carefully places the metal plate on which the design has been drawn. Great care must be taken while the etcher works with the acid.
The acid will not penetrate the wax or varnish, but it will eat away the bare metal where the needle has scratched away the wax. The acid will carve out a groove, which the etcher calls a furrow. The longer the etcher leaves the plate in the acid, the deeper the furrow becomes. Thin furrows will produce light lines while deep furrows will produce heavy lines.
When the line is exactly as deep as the etcher wants it to be, the plate is washed and the wax is removed by rubbing it off.
Next the plate is inked, so that all of the grooves are full. The plate is carefully wiped so ink remains only in the furrows.
Finally the plate is put into a printing press and it is covered by a sheet of paper. The ink is pulled out of the furrows by the pressure of the press and the design is transferred to a sheet of paper. The result of this effort is called an etching.
An etcher must master what is called the stopping out process. After the acid bath, some of the lines will be deep enough to produce just the right shade in printing. These lines must then be covered with wax and the plate is returned to the acid so the uncovered lines can be made deeper.
The etcher determines how many copies will be made from each plate. Some plates are used to make several hundred copies, although the lines in the artwork can become increasingly weak as the furrows in the plate are worn down by the printing press.
Sometimes an etcher will tone up the plate by adding what is called drypoint. Drypoint is scratching lines into the plate with a tool, rather than by creating the lines with acid.
Drypoint is more properly a branch of engraving rather than etching.
In drypoint, the needle like tool turns up a ridge of metal that is called a "burr." The burr is not removed, and when the plate is printed, the result is a much warmer and furrier line than can be obtained with the clean system of biting with acid.