The Dictionary Of Photography

A True Historic Record Of The Art & Practice Of Photography 100 Years Ago.

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Film Photography
The Supporting of Films in the Dark Slide or Magazine. The flat films, often called cut films, vary much in thickness, but they are seldom so thick and rigid as to be used like plates in the ordinary dark slide. Still the thicker cut films merely require a piece of black card behind each, as a protection against the springs which ordinarily serve to hold the plates well up to the faces of the rebates. The thinner cut films should be gripped in a film carrier, of which several patterns are sold, one of the best being merely a thin rim of metal hinged to a stout card, but in
F»g- 59-
the case of large sizes to a slab of ebonite, wood or metal (see fig- 59)- When a film is shut in between the rim and the card, the whole can be handled like a glass plate. Extremely thin and flaccid films are not generally used at the present time except in the form of bands for the roller slide, but sometimes it is con-venient to expose short pieces of thin film cut from the band. In this case this film may be stretched on blackened card by turning a little of the film over at each end of the card and fastening with gummed paper or postage-stamp edging. Another system for very thin films (and also available for the thinner " cut films") is to temporarily mount the film on a slightly adhesive surface. Plates of thin aluminium or of ebonite, coated on one side with a mixture of gelatine and glycerine (soft gelatine i part, water 2 parts, glycerine 3 parts), are very convenient, as the film adheres readily and strips off easily. A coating of lead plaster or lead soap (the Emplastrum Plumbi, formerly Empias-trum Lithargyri of the Pharmacopoeia) is a good and permanent adhesive, but in cold weather it is necessary to very slightly warm the coated surface.