This section is from the book "Complete Self-Instructing Library Of Practical Photography", by J. B. Schriever. Also available from Amazon: Complete Self-Instructing Library Of Practical Photography.
CaSO4 + 2H2O. Plaster of Paris; Gypsum.
Fine, white powder. Soluble, with difficulty, in water. If mixed with a small quantity of water, so as to form a paste, it will gradually thicken afterwards, solidifying to a hard mass of hydrated sulphate. Should be kept in air-tight glass-stoppered bottles. Useful for mending leaks or repairing broken bottles. If stale, heat to 4000 Fahr., before using.
Essentially a light-tight box with a lens at one end and a means for supporting a sensitive plate or film at the opposite end at right angles to the axis of the lens. Various modifications have been made to this simple form of construction for various purposes.
A camera made to look as little like a camera as possible, or one which is capable of being used to take pictures when hidden from sight.
An instrument usually employed in making ferrotypes. Contains a number of small lenses, each being partitioned off. It is thus possible to make several images upon the plate at one time.
Film cameras are of two general forms, one being of the box type, the other the folding type of construction. In both roll films are used in place of dry plates.
This is a form of camera in which either cut films or plates may be used. The films are arranged in what is known as a film pack, and this latter is inserted in the film pack adapter, which takes the place of the regular plate-holder. Camera, Fixed Focus - I, 69, 70.
A camera in which the lens cannot be moved for adjustment. The lens is focused for practically any distance within certain limits. (See Lens, Fixed Focus.)
One of the most compact forms of construction for cameras. When closed the bed of the instrument forms one side and the bellows being operated on a track is brought together inside of the box, thus reducing the bulk.
A convenient form of camera which can be operated when held in the hand. Usually the front portion holding the lens slides into the box, which latter is then closed by raising the bed.