Motography (Jan-Jun 1913)

May 3, 1913 MOTOGRAPHY 311 emulsion. After the emulsion has been thoroughly dried, the film is split up into ribbons of the finished size (1^ inches wide). The process of pouring the emulsion upon the film is very simple and effective in securing an even coating. Different emulsions are used for the positive and negative films, the emulsion of the negative being much Fig. 22. Centrifugal drying machines for removing all traces of moisture from the cotton. faster than that of the positive, as is the case with dry plates and lantern slides. DEVELOPMENT OF THE NEGATIVE. After the picture has been taken, the camera man delivers the film to the negative developing department, where it is developed and fixed in a manner very similar to that adopted in developing still pictures. Before proceeding with the development of the entire film, when the exposure and light conditions are unknown, a short piece is cut off and developed independently, so that the proper treatment may be determined without endangering the entire reel. In some plants the exposed film is wrapped spirally around a light rectangular frame or rack, for convenience in handling, and is then dipped into a tank containing the developing solution. This arrangement enables the' operator to agitate the film in the solution and examine it without danger of injury to' the delicate sensitized surface. After the negative has been developed to the requireddensity it is placed in the fixing bath of sodium hyposulphite where it remains until all of the active emulsion is reduced, and is no longer affected by the light. " Fixing having been completed, the film is thoroughly washed in clean water to remove the last traces of hypo, and is then given a final treatment in a dilute solution of glycerine and water. A small percentage of the glycerine remains with the film even after it has been dried, and owing to the moisture absorbing properties of the glycerine enough moisture is retained to keep the film in a soft and pliable condition. When the glycerine has been lost after a considerable service, by evaporation or other cause, the film becomes brittle and must be given another treatment in the glycerine bath. The film is dried upon large revolving wooden drums, usually driven by power. The motion of the drums throws off any small drops of water that mav adhere to the back of the film and keeps a constant stream, of warm air moving over the emulsion side. For convenience in developing long films they are often wound around large drums similar to the drying drums. After the film is wound on the drum it is suspended over the developing tank in such a way that lower edge of the drum and the film dips into the solution. The drum is now revolved until the negative isdeveloped to the proper density, and then is transferred to the fixing and washing baths. In taking "topical" films or news items for the "weeklies" different sections of the films are exposed under different light conditions or on different days,, with the result that some portions of the film are under and others over exposed. This makes it impossible to develop the film in a single length, for each exposure on the film now requires separate treatment. For the information of the developing department, the camera man places a punch mark at the beginning and end of each of the different exposures. When a film of this nature is received, the developer immediately unrollsthe film, cuts it apart at the punch marks, and develops each part separately. After drying, the pieces that relate to the same subject are sorted out and cemented together so that they form a continuous strip. The subtitles and leaders are inserted at the proper points and the film is carefully examined for mechanical defects. The completed negative is projected on the screen before the heads of the various departments who decide what is to be trimmed out of the picture to bring it within the desired length. When these alterations have been made, the film is given a second showing, and after further criticism all weak and unnecessary parts are eliminated. In making the titles and sub-titles a set of block letters are generally used, the letters that form the words of the title being arranged in the proper order on the top of Fig. . 23. Scene in a typical developing room showing the developing tanks. a table. A series of pictures is then taken of the letters by a motion picture camera pointed down toward the top of the table. In the film the titles appear as a series of small photographs, very similar to the small pictures. When written messages are used for sub-titles, the original is lettered on a large sheet by the draftsman. In a few of the plants all of the sub-titles are lettered by hand, but as this is a tedious process it is not as desirable as the block system. Titles in which the lettersmove across the screen and arrange themselves to forms