Motography (1912)

February, 1912. MOTOGRAPHY 75 Problems of the Operating Room By William T. Braun FILM. FILM STOCK forms one oi the most important pans oi the motion picture industry. Most operators know that it is inflammable, tears apart easily, and causes more or less trouble, but beyond that their know 1eiIP *es. It operators understood the composition. manufacture, and pr photography better than thev the film would be handled more carefully and intelligently. The inside oi the modern motion picture factory is a mystery to most operators on account oi the difficulty in obtaining permission to go through the plants ; therefore a short review i^i the various stages of manufacture up until the film reaches the exhibitor will not be ami — . MANUFACTURE OK STOCK. When the him stock reaches the motion picture factory jt con-ist ,.f strips >^i celluloid lj£ inches wide. 800 feet long, and is coated with a photographic emulsion. The pro naking the celluloid film and the emulsion are entirely separate. Celluloid is made from gun cotton and camphor. The gun cotton i< made from raw cotton saturated in nitric and sulphuric acids. After this it is washed and dried. Treating the cotton in this manner makes it a very explosive article. The camphor i then dissolved in alcohol. A layer of gun cotton is placed in a tank over which the camphor is sprinkled. Several lavers are placed in the tank in this manner. The gun cotton i< dis d in the camphor and sinks in the form of celluloid to the bottom of the tank. The lumps of celluloid are next worked between hot and cold rollers and then pressed in hydraulic presses and dried. The stock is worked into strip 1 Ion Qf an inch in thicknes-. 82 inches wide, and 200 feet long. These strips of celluloid are passed under a hopper having a slit or mouthpiece the entire width of the strip. The celluloid passes under the hopper at a uniform speed and the emulsion flows out upon it. giving it a uniform coating. A bromide emul>ion i u-erl for coating the film to be u prints, a it is dower than the nitrate emul u-ed for coating the stock used for negati-. These pieces of film are then dried and cut into Strips ide. The film is packed in tin can-. 200 feet in each, and sent to the motion picture manufacturer. Film is highly inflammable, but not explosive. It will not take fire unless a flame i applied directly to it. or if a light of great heat inten-ity. -uch a the projection arc. is allowed to shine on it for a short time. Film will ignite at the aperture from the heat of the light rays in from three to thirty seconds, depending upon the strength of the light and the condition of the film. .V.n-in flammable film is used very litth , jt deteriorate rapidly with The majority of motion picture manufacturer • forate the film then counts for the fact that some pictures are steadier upon the screen than others, although run through the -ame projection machine. Perforating machine: eating and rotar;. right h ach picture punched at one time with the recipi perforator; the film i then drawn forward and another set of hi are punched. The film is fed forward by an intermittent device, similar to that of the projection machine, between the strokes of the punches. The rotary perforator consists of two drums, one oi which has teeth on it similar to a sprocket; the other drum having depressions on its face corresponding to the teeth oi the other drum. The strip oi film is fed between the two drums and perforated. The rotary perforator will perforate from five to ten times as much stock per hour as the reciprocating machine, but is not as accurate. The perforating of the film is done in the dark room. PHOTOGRAPHY. The motion picture camera has many things in common with the projection machine. At the top of the camera is the upper film holder, which carries the roll of unexposed film. This corresponds to the upper film magazine. The intermittent movement of the camera is generally of the claw type, similar to that used on some of the older makes of projection machines. A disk-type shutter is placed between the film and the lens -imilar to the revolving shutter of the projection machine. The period of darkness is much greater in the camera. A lens of about three inches focus is used on the camera. The crank of the camera perform the -ame office as that of the projector. There is also a trick crank and reversing crank found on the camera. After leaving the camera the film enters the take-up box. similar to the upper one. A finder for the focusing window ; an indicator showing the amount of film used ; a speed indicator showing the speed of the camera, and a heavy tripod completes the principal parts of the camera. The usual speed of taking pictures i< fourteen per second. The camera man must be very careful to turn the crank at the uniform speed. Also the camera i not secured like the projecting machine, so that he must not put his whole weight on the crank a> somJ moving picture operators do. The speed of the crank must be uniform throughout the entire revolution, otherwise some of the pictures will be under or over-exposed. The usual exposure i three-eighths open. This means that when fourteen pictures are taken per second, the lens i open 1 :'o of a second for each picture. The trick crank generally takes but half the pictures per second that the main crank does. Consequently, when the picture are projected upon the screen the action i twice a fast. When the exposed films from the camera and the printed films reach the developing room they are wound on drums three feet in diameter. Each drum or holder carrie 200 feet of film. The drum are supported oyer the zinc developing trays and revolved, the film passing through the developer. When the film i developed the drum are placed over the wash trays and turned a few times. After passing through the second wash water they go to the fixing bath. The film i next washed in running water, and then given a bath in diluted glycerine, after which it i taken to the drying room. The film i wound on drying drums driven by a motor. When the film i dry it i taken t" the inspection room. Title are made by placing the letter on the t<>p "I a table and the moving picture camera i placed above the table. Titles and sub-titles for an entire reel ally prepared in one -trip, developed, and then cut ii nd spliced in the pr. .per place in tl