Amateur movie making (1928)

246 AMATEUR MOVIE MAKING Picture Becomes Stationary : Motor stops. Current supply to motor is too weak or motor connection is broken. Motor runs. Suspect torn perforations. Open gate and examine film. Move film down until fresh perforation is engaged. Single frame clutch thrown out. "Bain" Effect: In this case the picture looks like it was being viewed through a heavy rainstorm. The effect is produced by the film being pulled down before the shutter closes. The fault lies in a loose or slipped shutter. Loosen shutter on shaft, then turn until the intermittent just starts to pull film down. Place shutter so that its front edge covers the aperture and fasten in place. Now rotate the mechanism slowly and see if the film stops dead still before the shutter uncovers the aperture. This will remedy the fault. Perforations Appear upon Screen : This is followed by a film stop. It indicates that the film has jumped from the gate or sprocket and this usually means a torn film also. Stop machine, remove damaged film from gate, rethread and proceed with projection. Film Chatters in Gate : This is usually accompanied by a dancing of the image upon the screen, by a loss of focus and general poor projection. The cause is an accumulation of gum from the film. This is a mixture of softened gelatin from the emulsion, hardened lubricant and dust. It is about of the consistency of cold shoemaker's wax or harder. This mass becomes tacky when slightly warmed by the heat of the lamp and friction. This drags upon the film surface just as rosin will cause the finger to drag and "chatter" when a rosined fingertip is rubbed upon glass. The mass is removed by a horn or hard rubber scraper. Never use metal for this purpose. Metal will scratch the gate, and these scratches will act as tiny chisels which in turn scrape more gum from the film thus aggravating the trouble. If the mass does not come away easily, moisten it. This makes removal much easier.