ENGRAVING A term given to processes in which, by photo graphy and subsequent manipulation, a printing surface is obtained in which the parts receiving ink stand up in relief like type characters. Thus line and half-tone etched blocks may be said to be photo-relief engravings, but the term is pro perly applied to processes of making a hardened gelatine relief which may be printed from as in the Pretsch process, Dallas process, Husnik's Leimtype, and the swelled-gelatine process. The Woodburytype process is often termed a photo relief one, although here the image itself is in relief, the printing block being an intaglio one. The acrograph process may be correctly de scribed as photo-relief engraving.
An instrument on the old peep-show principle, for enabling a number of persons simultaneously to view animated photographs in daylight.
Also the name of a particular make of kine matograph machine invented by W. C. Hughes.
A term which had its origin in 1863, when the sculptor Willeme, of Paris, patented his process and set up a studio for the work. He photo graphed his models with a number of cameras placed at the sides and top of a kind of building having a cupola ; and he afterwards utilised the photographs in constructing the model, employ ing pantographs in order to facilitate his work. Poetschke, in 1891, improved the process, and Selke, a year later, substituted for the ordinary photographic apparatus the kinematograph, and projected on to the sitter a shadow which advanced progressively in the direction of the kinematographic camera. In this manner, ac cording to Carlo Baese, the apparatus registered a considerable number of silhouettes correspond ing to the number of parallel planes in the model. Each of these negatives, about soo in all, had to be enlarged separately upon bromide paper, and each was then pasted upon card and cut out with scissors. When these silhouettes had been cut into sections, they were stuck one over the other, and so built up, it is said, to form the portrait, but exactly how it was done has not yet been made clear. The use of bichromated
gelatine (discovered in i85 ) is more satisfactory. (See " Relief, Photographs in.") For artificial reliefs—that is, prints that appear to be in relief—see "Plastic Photographs." Carlo Baese, who has paid particular attention to the production of portraits in the form of medallions, works on the lines described under the first named heading, and secures better modelled effects than are possible in the ordinary way, by the use of an optical lantern and mirrors, by which he projects and reflects light upon certain parts of the face which it is desired to show in high relief. His process was described before the Royal Photographic Society, on October 191o, and by its means wonderful results are obtainable.
The term " photo-sculpture " is also applied to a kind of trick photography. A sketch of a bust without the head is made, natural size, on a sheet of cardboard, which is then cut out or, preferably, a papier mache arrangement may be purchased ready for use, and placed on a pedestal of a convenient height, the sitter being posed behind it in such a way that the living head " sits " realistically. A photograph is next taken. Parts of the image that are not required may be scraped from the dry negative, or a print is made, blocked out with black or red water-colour paint, and copied in the camera. Another method is to cover the parts (arms, etc.) of the figure not required with a black cloth. The background should be quite black, and it may be necessary to powder the hair, eyebrows, etc., to give them, in the photograph, the appear ance of stone.
A term applied to a substance that is sensitive to light.
(See " Spectro pho tography." ) A stereotype made from a plaster cast taken from a gelatine relief. (See " Swelled Gelatine Process" and " Wash-out Gelatine Process.") The term has also been applied in America to a block made by reproducing a drawing obtained from a photograph by the bleaching-out process.