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.
Premo Cut-Film Developing Tank. The Premo Cut-Film Developing Tank is the latest application of the tank principle. The Premo tank provides for the development of cut-films, or the films from the film-pack, with a minimum of care and labor, and the assurance of uniform results. The Premo Film Tank, unlike the Kodak Roll Film Tank, must be loaded in the dark, but development may be carried on in daylight.
259. The Premo tank consists essentially of two pieces - a metal receiver or frame for holding the films, and a tank with cover for the developing solution. The receiver is divided into twelve compartments, in all sizes except the 5x7 size, which has but six, each compartment accommodating one film. As the film is taken from the pack it is held between the thumb and fingers, slightly curved from top to bottom, and slipped into its respective compartment. (See Illustration No. 29.) When all compartments are filled the receiver is placed in the tank, which has been previously filled with the developer. The top is then replaced and the films are left to develop for a certain specified time. No further attention is necessary, excepting to turn the tank, end for end, three or four times during development. At the expiration of the full time open the tank, take out the receiver, remove the films, place them in a tray of water for a moment, then transfer to the fixing bath. When the development is completed rinse out receiver and tank, and set them aside to dry. If desired, films may be fixed in the same tank in which they were developed, but this is not recommended.
Note. The operation of removing films from the pack and loading the receiver is done in a darkened room, by the light of a ruby lamp. During the day any darkened closet will suffice. To place the film in the receiver will require only two or three minutes, and as soon as the top is placed on the tank it may be brought out into any light and left until development is completed.
261. It is very seldom that films can be developed and prints made from them the same day; therefore, as the majority of amateur photographers find it more convenient to develop at night, we would suggest night time as being particularly appropriate. Any room can then be made perfectly dark and may be employed for loading the tank, after which the developing may be carried on in a lighted room.
262. If desired to develop less than a dozen films, one merely removes from his pack those films that have been exposed, and places them in the receiver as previously described.
Developers For Kodak Film Tank. The tank developing powders will be found very convenient to use for either the film or the plate tank. These powders are compounded in accurate quantities, to be dissolved in a given amount of water. The powders are supplied in different size packages, so it is possible to make either a large or small bulk of solution to suit the size tank employed. For amateurs who prefer to make up their own solutions, the formula given in paragraph 504, Chapter XIX (Gum-Bichromate Process), of Volume II, of this library, will give excellent results in the tanks herein described, with a twenty-minute developer.