When we visit an art gallery we find pictures in all mediums—oil, water color, pastel, charcoal, pencil, pen and ink; and then farther on we find photographs, etchings, engravings (steel, copper, and wood), and lithographs.

It takes much careful study and practice before we can expect to recognize the medium or process used. Most of us recognize water color, oil, pencil, charcoal, and pastel work, but prints made from engravings, etchings, and photographic plates are more difficult to distinguish.

At the time most of our famous old masters were painting, photography was unknown and the first etchings and engravings were laboriously done by hand and usually by the artists themselves. Now, the time and expense of hand work are so great that, although the important lines are still put in by hand, yet the camera plays an essential part in most etchings and engravings. Originally the artist drew direct on the steel, copper, or wood block, but as the drawing must be reversed, it required a great deal of skill to do this. It was only after much practice that the engraver could reverse his sketch as he drew it, and in most cases he either made a reversed study on paper to work from, or fastened his drawing opposite a mirror and drew from that. As soon as photography came into use all this was simplified, as the drawing was reversed in the photograph and much time was saved. In the case of wood engraving, which is the cheapest and most perishable, the picture is photographed directly upon the block of wood. The steel, copper, or zinc plates are often covered with some waxy substance and the design drawn upon them with fine engraver’s tools. After the drawing is completed there are three distinct processes of engraving:

1. The lines of the drawing are sunk below the surface of the plate, as in etchings and steel and copper-plate engravings.

2. The background is cut away or eaten by acids, leaving the lines in relief as in wood engravings, half tones, and zinc plates.

3. There is no relief or depression, but the surface is smooth, as in lithographs.

In etchings and steel and copper plates the surface is usually covered with a waxy substance, or something which resists the action of acid. Then it is often smoked so that it will be easier to see the lines of the drawing which are made with fine steel tools, cutting through the wax to the surface of the metal. It is not the intention to cut the metal, but merely to scratch through the coat of wax to expose the metal. Then the plate is put in acid, and each line is eaten into a groove varying in depth according to how long it is left in the acid. If some of the lines are not deep enough, the rest of the plate may be covered with the waxy substance and it may be put in the acid many times until all lines are the desired depth.

A print is made from this plate by covering it with ink, allowing the ink to fill the grooves, and wiping the rest of the plate clean. Then paper is pressed upon it.

Rembrandt ranks first among etchers. Other well-known artists are Albrecht DÜrer, Van Dyck, and James McNeill Whistler.

In wood engravings, half tones, and zinc plates the picture is either drawn or photographed upon the plate. Then the spaces between the lines are either cut away with the sharp steel tools of the engraver, which vary in shape and size, or, the lines being protected by the waxy substance, the surfaces between are eaten away by acid. Thus the original lines are raised higher than the rest of the plate. The raised lines are then inked and pressed against the paper. A wooden block may also be molded into a “metal cast” in order to preserve the engraving.