A Treatise on Etching

Excerpt

Definition of Etching.—To be able to get an impression on paper from a metal plate in a copper-plate printing-press, it is necessary to sink the lines of the design below the surface of the plate, so that each line is represented by a furrow. The plate is then inked all over, care being taken to fill each furrow, and finally the ink is cautiously wiped away from the surface, while the furrows are left charged with it. A piece of moist paper pressed against a plate so prepared, will take the ink up out of the furrows. The result is an impression. In engraving proper these furrows are cut into the plate by mechanical means; in etching chemical means are used for the same purpose. If nitric acid is brought into contact with copper, the acid corrodes the metal and finally eats it up altogether; if it is brought into contact with wax or resinous substances, no action ensues. Hence, if we cover a copper plate with a ground or varnish composed of wax and resinous substances, and then draw lines upon this ground with a steel or iron style or point, so that each stroke of the point lays bare the copper, we shall have a drawing in lines of copper (which are affected by nitric acid) on a ground of varnish (which is not thus affected). If now we expose the plate to the action of nitric acid for a certain length of time, we shall find, upon the removal of the ground by means of benzine, that the lines have been bitten into the plate, so that each line forms a furrow capable of taking up the ink. The depth and the breadth of the lines depends upon the thickness of the points used, and upon the length of time allowed for biting; or, in other words, by varying the size of the points and the time of exposure the lines may also be made to vary. This is the whole of the science of etching in a nutshell.

2. Requisites.—The following tools and materials are the only ones which are absolutely necessary for a first experiment:—

1. A Copper Plate on which to execute your etching. Do not waste your money on a large plate. A visiting-card plate is sufficiently large. If you happen to have an engraved plate of that kind, you can use the back of it. If you have none, get one at a card-engraver's. The price ought not to be over fifteen cents. If you do not live in any of the large cities named above, or cannot find a card-engraver, send fifteen cents in stamps to Mr. Geo. B. Sharp, 45 Gold St., New York, N. Y., who will forward a plate to you by mail. Be very particular in giving your full and correct post-office address. These plates only need cleaning to fit them for use.

2. Benzine, used for cleaning the plate, sold by grocers or druggists at about five cents a pint for common quality.

3. Whiting or Spanish White, also for cleaning the plate. A very small quantity will do.

4. Clean Cotton Rags.—Some pieces of soft old shirting are just the thing.

5. Etching-Ground, with which to protect the plate against the action of the acid. This ground is sold in balls about the size of a walnut. If you do not live in a city where you can buy the ground, you may as well make it yourself....