The Laughing Faun/Greek Marble Roton

A Hyalograph, similar to a cliches verre, is a photographic process derived from scratching on glass with a needle then transferring the image through the action of light to a sensitized copper plate. Then etching and printing the plate. The process was invented by Dujardin, who is said by Hamerton to have used it for scientific illustration. The glass was given a fine and even grain, after which the artist drew on it with a lead pencil, stump, or brush with diluted Indian ink. The drawing was then printed down on to a metal plate covered with a sensitized etching ground, and the plate was washed and etched after exposure. The results are impressive, showing fine tones. From Greek words for glass and print. A hyalograph is a drawing on glass—not common ground glass, but dispolished for the purpose with a very fine and even grain. The instruments used are chiefly the lead-pencil, the stump, and a brush charged with more or less diluted Indian ink. The drawing is transferred by light to a sensitized etching-ground, though the camera is not employed and there can be no reduction. The process was invented by M. Dujardin, the well-known heliograveur, and employed for scientific purposes. The process is, however, excellent for original work, because the reproduction, being so very direct, loses less than by any other process known—in fact, the loss is almost imperceptible, which cannot be said for any other photographic process. In the hyalograph the intervention of photography is reduced to a minimum—the passage of light through the glass. The plate is bitten like an aquatint. (montgomery)