The motion picture projectionist (Oct 1927-Sept 1928)

October, 1927 The Motion Picture Projectionist 41 Definition of Terms Pertaining to Films and Projection Aperture — The opening thru which the light passes between its source and the screen. The film passes vertically at the aperture. Cement — A chemical solvent used to join two pieces of film together. Ether is one of its active constituents. Film cement evaporates quickly, therefore should be kept in tightly corked containers. Exchange — A central depository from which film may be bought, rented, or borrowed. Film Mender — A clamp-like device used to facilitate the splicing of film. Footage — Refers to length of a roll of film. Frame (noun) — Refers to a single photograph in the roll of film. There are 16 frames to every foot of standard film. Frame (verb) — The operation of correctly aligning the picture on the screen. "Framing" is accomplished by moving a lever or some other similar device. Frame Line — The line that divides the top of one image from the bottom of the other. This line is observed when picture is in mis-frame on the screen. Geneva Movement — A form of intermittent movement first used in Geneva, Switzerland ; hence the name. It is the form of intermittent movement that is most used. Intermittent — The device that moves the film normally at 16 frames per second. Leader — Blank or opaque pieces of film at beginning of the reel placed immediately ahead of the title. It is placed there to facilitate threading the projector and to protect the first few feet of the title. Legend — Titles and Subtitles — Words of explanation descriptive of various scenes in the film. Loop — Slack places left in the film, one immediately above the aperture and another immediately after the intermittent sprocket. Mazda Equipment — The incandescent lighting unit used in professional projectors. All portable and semiportable machines are equipped with incadescent lamps. Carbon arcs are used in professional projectors. Where it is necessary to project pictures at great distances carbon arcs are always used. Mazda equipment is coming to be used more and more as times goes on, for shorter projection distances. Misjramc — Caused by an improperly spliced film, or incorrect threading of projector. Operator — The individual who manipulates the projection apparatus. Perforations — Sometimes called sprocket holes — on both edges of the film. In standard film there are 64 perforations on each edge, per foot. Positive Print — Film exposed to light behind a negative. The positive is used in the projector. Patch — See Splice. Projector — An apparatus provided with the necessary devices for showing pictures on a screen. Projectionist — A skilled operator of motion picture apparatus— an expert. Rain Streak — Tiny scarlet, in the emulsion that soon accumulate dirt. Caused by dirty projector or "pulling down" film. Reel — The spool upon which film is wound. Sometimes the term reel refers to the film itself as well as the spool upon which it is wound. Rewind (noun) — A device used to change film from one spool to another either for the purpose of inspection or to make it ready for the next exhibition. Rewind (verb) — To change film from one reel to another. Screen — A surface upon which the picture is projected. Safety Shutter — Sometimes called fire shutter. The safety shutter is located between the film and the light source and opens or closes at the aperture automatically when the machine starts or stops. Shutter (Revolving) — The device used to intercept the light during the time the film is in motion at the aperture. The shutter also serves to minimize the flicker on the screen by increasing the oscillations of light and shade to such a frequency that the eye cannot detect them. Two blade and three blade shutters are in general use. Splice — A place where two pieces of film have been joined by use of film cement. Such a union is sometimes called a patch. Sprocket Wheels — The revolving toothed wheels that engage the perforations and thereby move the film thru the projector. There are usually three such sprockets ; one found immediately after the film leaves the reel ; the intermittent sprocket which jerks the film sixteen times per foot between the loops and the lower or take-up sprocket from which the film passes directly into the takeup reel.