ANASTATIC PROCESS (Fr., La Photo graphie Anastatique ; Ger., Anastatisch Druck) A method of copying line drawings by placing a sensitive material with its film side in contact with the drawings, and exposing to light through the back of the sensitive paper or plate. This process, originally invented by J. H. Player, has been rediscovered and elaborated by E. E. Fournier d'Albe, who has given it the above name. As in Playertype, it depends on the fact that the light passing through the plate or sensitive paper is reflected back to the film from the white surface of the plan or drawing, whereas the dark lines of the latter reflect hardly any light. If plates are used, the photo mechanical kind is best. The exposure is about the same as would be required to make a positive transparency from an ordinary negative on the same kind of plate. A quick-acting developer giving contrast is to be preferred, as, for example, hydroquinone with caustic potash, or a i in 15 solution of rodinal. The slight fog that occurs in the lines may be removed by a brief immersion in a ferricyanide and " hypo " reducer after fixing and washing, following this by at least half an hour's further washing.
A positive instead of a negative may be pro duced by soaking an unexposed dry-plate for five minutes in a io per cent. solution of potas
sium bichromate and allowing it to dry, of course in non-actinic light. This is exposed to daylight through the glass side, in contact with the draw ing to be copied, and is developed with a dilute rodinal solution. The parts which have received reflected light from the drawing are rendered more insoluble than those parts in contact with the darker portions, and the latter in conse quence alone absorb the developer. It follows that the lines of the original are developed out, while the background remains white or nearly so. The positive is fixed in " hypo " as usual. Copies can also be produced by this process on bromide paper, and there are many other ways in which the process may be applied. It is immaterial if the drawing has printing or other matter on the back. Distinctive points of this process are that no camera or lens is employed, and that the copy is exactly the same size as the original.
Anastatic photography must not be confused with the anastatic lithography process described below.