Moving Picture Age (Jan-Dec 1921)

10 MOVING PICTURE AGE May, 1921 Visual Instruction in the Schoolroom III. The Care, Use and Abuse of Film The effectiveness of many an exhibition has been marred by film troubles. This able discussion illustrates the methods by which you may achieve worthier showings and incidentally improve the exhibitions of others By Charles Roach In charge of Visual Instruction Service, Iowa State College of Agriculture and Mechan c I Arts, Ames, Iowa IN the preceding article we pointed out some general considerations pertaining to the selection of projection apparatus for non-theatrical institutions. Assuming that a satisfactory equipment is properly installed, we may now give some careful consideration to the physical condition of film in order that the best service may be had and visual instruction work be carried on satisfactorily. A reel of motion picture film is a thin, fragile strip of celluloid \y% inches wide and about 1,000 feet long, upon which are printed sixteen pictures per foot. There are two kinds of stock in common use : the nitrate of cellulose (inflammable) and acetate of cellulose (slowburning). The nitrate stock predominates. Perhaps not one reel in a thousand is now printed on the acetate stock. Not only is the nitrate film cheaper, but it retains its pliability much longer, breaks less easily, and has a longer life. Nitrate of cellulose is highly inflammable, but, contrary to the idea of some, it is not explosive. It will burn when subject to an open flame or placed near great heat. Film should be kept in metal containers properly insulated from heat and flame. Under no circumstances should film be handled by a person who is smoking. It is unwise to place film near a fireplace, heating stove, gas jet or oil lamp. Precaution should be taken while it is being transferred from container to projector, or vice versa. He who fills a gasoline stove tank never strikes a match to see if the tank is full ; neither would he permit a burner to be lighted during the operation. Film is far less dangerous than gasoline, and if handled with the same care is no more hazardous. The slow-burning film, sometimes called "non-inflammable" or "safety" film, will burn about as readily as paper. It may be identified by the word "Safety" printed along the edge at intervals about one foot apart. Teachers are urged to take such necessary precautions as are prescribed by law of state and municipality; then, whether safety or inflammable film is used, protection is afforded at all times. Why Inspection Before Showing Pays Film, when received from the exchanges, usually comes rewound, yet infrequently ready for the projector. Every reel should be rewound slowly on a bench, and every foot should be examined for poor, harsh, dry and improperly made patches, tears, broken sprocket holes, and other imperfections that may have accumulated during the several weeks or months of previous use. The exchanges ought to send film in perfect condition, but they seldom do. Unless the operator is willing to suffer frequent breaks and thus invite undesirable comment, there is no alternative. He must inspect every foot of film before it is projected ; this is his only protection. Inspection is really a simple procedure. The reels should be placed so that the film, while being rewound, travels from left to right, winding the emulsion side out. The film should be grasped between the left forefinger and left thumb with just enough pressure to slightly cup the film. It is possible to detect every broken sprocket, tear and patch if rewinding is done slowly — with emphasis on "slowly." The broken sprocket hole should be cut as indicated by "b," Fig. 1. The defect may pass through a projector perfectly without making a previous repair, but the probabilities are that one part will catch on the idler, tear the film, lose the loop, and otherwise damage the film, which would necessitate stopping the machine. The safest and wisest plan is to make the repair. How Repairs Are Made It is not surprising that film sometimes breaks, even when handled carefully. The repair is so simple that a child can make it, yet of all the abuses and evidences of inefficiency none are so self-evident as poor patches, nor are any abuses as inexcusable. If, somehow or other, operators would recognize the importance of making a patch properly it is possible that half of the film troubles would not appear. Fig. 2 illustrates the tear. Fig. 3 represents how one end of the film ("a") should be cut immediately on the frame line, while the other end ("b") is cut about one-eighth inch beyond the frame line. Fig. 4 shows the emulsion scraped from "b." A safety-razor blade may be used very satisfactorily. At this point many operators fail. All of the emulsion should be removed up to the frame line. Where the emulsion is removed superficially a firm patch is an impossibility. The next operation is equally important, though oftentimes done carelessly. A very small amount of film cement should be applied to the film, and the ends so superimposed that the frame line of one end coincides perfectly with the frame line of the other. In addition the edges of the film must align perfectly, all surplus film cement must be wiped off, and pressure firmly and evenly applied over the patch for from three to five seconds. The work must be done very rapidly. Partially dried cement loses its holding qualities. When it is understood that a film patch resembles a weld rather than an adhesion, it is easy to see that a perfect patch is made more readily by a film-mending device than by merely using the fingers, especially since pressure can be adequately and evenly applied by the mender. Its cost is insignificant when compared with the service it will give. No projection room can afford to be without one. Fig. 5 needs no further comment. It shows the film properly mended. Attention is called to Fig. 6. This illustrates a common mistake. The emulsion was scraped beyond the frame line. When projected, this film would cause an unsightly flash of light on the screen. Care would have made this a perfect patch, but carelessness made the patch hard and dry as well as very dirty. Misframes are evidence of carelessness. Fig. 7 shows a patch made without regard for the frame lines. When this film was projected the "optience" was shocked by seeing the top half of the picture on the lower part of the screen and the bottom half on the upper part of the screen, until the operator could manipulate the framing lever. Misframes are never seen on the screens of firstclass theaters and should never be seen anywhere.