An Etcher's Studio.
From the Third Edition of Abraham Bosse's “Treatise,” Paris, 1758.
A TREATISE ON ETCHING.
CHAPTER I.
DEFINITION AND CHARACTER OF ETCHING.
1. Definition.—An etching is a design fixed on metal by the action of an acid. The art of etching consists, in the first place, in drawing, with a point or needle, upon a metal plate, which is perfectly polished, and covered with a layer of varnish, or ground, blackened by smoke; and, secondly, in exposing the plate, when the drawing is finished, to the action of nitric acid. The acid, which does not affect fatty substances but corrodes metal, eats into the lines which have been laid bare by the needle, and thus the drawing is bitten in. The varnish is then removed by washing the plate with spirits of turpentine,[2] and the design will be found to be engraved, as it were, on the plate. But, as the color of the copper is misleading, it is impossible to judge properly of the quality of the work done until a proof has been taken.
2. Knowledge needed by the Etcher.—The aspirant in the art of etching, having familiarized himself by a few trials with the appearance of the bright lines produced by the needle on the dark ground of smoked varnish, will soon go to work on his plate confidently and unhesitatingly; and, without troubling himself much about the uniform appearance of his work, he will gradually learn to calculate in advance the conversion of his lines into lines more or less deeply bitten, and the change in appearance which these lines undergo when transferred to paper by means of ink and press.