Amazing articles on just about every subject...

Projectors And Projecting

( Originally Published 1924 )

WHEN, by the aid, or in spite of the foregoing chapters you have obtained a film ready to show, you come to the last step in cinematography, and one which many cinematographers know little of. This is projection. In professional work the projector is a man who has specialized in this branch of the work and rarely, indeed, does the cinematographer project his own film, but the amateur must add to his dual role of director-cinematographer, the third part of the work, projecting.

The variety of projectors offered is if anything wider than that offered in cameras. Projectors may be briefly classed as follows: (1) Professional or theatre projectors; (2) Semi-portable of school type projectors; (3) Portable or lecture projectors; (4) Home projectors; (5) Sub-standard projectors and (6) Toys.

The Professional type of projector is a bulky machine which may stand some six or seven feet high and weigh a half a ton or more. The usual type is about six feet high. The light is an electric arc for long throws, and a special concentrated filament in-candescent lamp for smaller theatres. The unit ma-chine consists of a retort and receiver magazine, intermittent movement, fire gate, lamp house and supporting standard. The refinements include motor drive, automatic speed control and indicator, metal housings for all moving parts, stereopticon attachment for showing lantern slides and so forth. The light is movable in relation to the lamp house and the whole lamp house moves forward and back. The projector runs forward only, and there is a metal door which drops between the light and the film when the machine stops. This is necessary for the standard film is highly in-flammable and the intense light used would ignite the film instantly if allowed to strike it while it was not in motion. Sometimes even the slight fraction of a second which it is exposed to the light in projection is long enough and the film ignites in running. For this reason fire-proof booths are required by law in all places where a professional type of projector is used.

The professional operator must understand the adjustment of his light, of the condensor lenses, and the adjustment of the mechanism. He should be able to catch the end of the broken film and keep it running through the projector without interruption. He should be able to adjust the frame to the aperture before starting the machine and should have his lens focused before the exhibition starts. The trained operator has his hands full while at work, and the professional projector would prove entirely impractical for amateur use, although its cost is not great. A very good professional projector will not cost in excess of one thousand dollars and many theatres use projectors which cost three hundred dollars or less.

The semi-portable type is a small edition of the professional type, but some of the adjustments are fixed, and the operation is simple enough for the ordinary school-teacher to learn to operate it without trouble. This type of projector usually has an incandescent lamp and motor drive. It usually has fire trap throats on the magazine so that if the film ignites only that portion will burn which is exposed between the magazines. However, they are licensed for use with standard film only with an enclosing booth.

The portable projectors are getting into the real amateur class. They usually resemble a small suit-case and are self contained, including a motor for driving the mechanism. Many of these projectors, designed for short throws, that is up to forty feet, have the lighting and optical systems so arranged that the projector may be stopped and a single frame projected without danger of igniting the film even though the inflammable film be used. Some have in addition a reverse movement which will project the film back-ward. This type of projector is often used by film editors in editing the film as a scene may be projected repeatedly without removing the film from the ma-chine. These machines have a capacity of a full one thousand foot reel and cost from one hundred dollars upward. Good used machines can be purchased for considerably less than one hundred dollars. These machines are licensed for use with non-inflammable film, but they are so nearly fire-proof, owing to their closed construction and the comparatively weak light source that they are widely used with inflammable film.

There are a number of home projectors on the market, which are of a skeleton type, resembling the old time theatre projectors but which project very well, indeed. The first of these to meet with any great popularity was the Home Pathescope. The usual projector has a shutter divided into four parts. Two of these are open and two closed, so that the light is permitted to pass approximately one-half of the time. The Pathe has a very rapidly moving intermittent which allows the shutter to be open somewhat more than two-thirds of the time, and this materially in-creases the illumination from a given light source.

The shutter used on this projector has three blades and three openings. A comparatively weak illuminant will give a brilliant image. This projector is made to take the Pathe Safety Standard film which is coated on non-inflammable base, so that it can be used in the home without infringement of the insurance regulations. If desired, this projector can be obtained in a cabinet which closely resembles a console model phonograph.

The Ica home projector is extremely simple and uses a low candlepower lamp close to the film. This projector uses standard film, but owing to the small size of the lamp, there is slight danger of igniting the film. The projector is extremely small and easily portable. It can be stored away in a small space and is entirely practical for home use. It is provided with five hundred foot reels, but one thousand foot reels can be used. It is used in hand or motor drive.

The Hall projector is a similar instrument, slightly more elaborate and is furnished to take either the safety standard or standard film. It throws a picture up to four by five feet, amply large enough for home use. It can be placed in a space 7 1/2 x 8 1/2 x 11 1/2 inches. It uses a 12-16 volt lamp, 32 candlepower. The resistance is contained in the extension cord and for use it is only necessary to attach the cord to any light socket. It is furnished in hand or motor drive, and with either 500 or 1,000 foot reels. It costs seventy-five dollars with 1000 foot reels and twenty-five dollars extra for motor drive.

The Vitalux film, of course, requires the Vitalux projector. This machine is finished in black flake enamel and operates by either hand or motor power. The light is a 110 volt, 250 watt projector bulb with concentrated filament. The socket is adjustable for centering the lamp in the optical axis. The machine with motor weighs twenty-five pounds and measures 7 1/4 x 12 1/2 x 143A inches. It is supplied as a part of the Vitalux outfit.

There are three standard projectors on the market for use with the sixteen millimeter sub-standard film. These are the Kodascope, supplied as a part of the Cine-Kodak outfit, the Victor projector, and the Bell & Howell projector.

The Kodascope is a beautiful instrument, the mechanism being largely enclosed in a black flake enamel case, and the whole being very compact. It is furnished with electric drive and has a capacity of 400 feet of film, equivalent to 1,000 feet of standard guage film. A film splicer is incorporated in the projector, or rather I should say, that it is furnished as a part of the projection equipment. The machine is motor driven. It is furnished as a part of the Cine-Kodak outfit and is not sold separately.

The Victor Cine projector .also uses the sixteen millimeter film. It is of unusual design in that the two reels lie side by side instead of one above the other as is usual except in suitcase projectors. It is of all metal construction finished in flake black enamel. The condensors are three in number and the lamp house is provided with a silvered spherical mirror behind the lamp. This gives a strong illumination with a comparatively small lamp. The lamp is 32 candlepower of 12 to 16 volts. A resistance is sup-plied as a part of the projector for use with 32, 104 to 120, 125, 220 or 250 volts. The 104 to 120 volt being supplied when not otherwise specified. The intermittent will operate more than one thousand hours without adjustment, and is easily replaced. It is adjusted at the factory. The ratio is 6:1. The flickerless shutter is adjusted at the factory and is entirely enclosed. The take-up is adjusted at the factory. The machine is furnished in hand drive only, the crank being turned two times per second, just as in using the camera. The projector may be stopped and a single frame projected as a still whenever de-sired. The spools hold 400 feet of sixteen millimeter film, although the projector will also take the 100 foot camera spools if desired. A picture 30 x 40 inches will be projected with a throw of sixteen feet.

The Bell & Howell is a very compact projector and as in their camera, this firm has made another step in sub-standard work. This camera is equipped with an automatic light stop, and forced air cooling and will meet all underwriters' requirements, especially as the sub-standard film is coated on non-inflammable stock. The motor is not in any sense an attachment, but is built into the body of the machine as an integral part thereof. This projector moves forward or back or stops for the projection of a single frame. It tilts upon its standard so that it may be used with a screen elevated above the heads of the spectators, or from a balcony, projecting downward. The intermittent is a 9:1 movement and the projected image is flickerless. The image may be projected life size, if desired, instead of being limited to a smaller size, about 30 x 40 as is the case with other sub-standard projectors. When folded this projector measures 6 1/2 x 9 1/2 x 10 inches and weighs nine pounds. It has a capacity of 400 feet of film.

In projecting motion picture film, the first consideration is the length of the room in which the projector is to be used. The size of the image depends upon the distance of the projector from the screen. Thus, a sub-standard projector is listed to throw a 30 x 40 inch picture at a distance of sixteen feet. If the projector is moved nearer the picture will be smaller but brighter. If moved farther away it will be larger but dimmer. So if the projector is listed to throw a 30 x 40 picture at sixteen feet it is presumed that any larger image will be too dim for convenient use. In professional work, lenses of different foci are supplied whereby an image of a given desired size can be obtained with the throw most convenient for the size of the theatre in which it is to be used.

The projector is a machine which must operate rapidly and accurately, but it is built more ruggedly than the camera. It should be kept well oiled at all times, but oil should not be allowed to accumulate, for an oil spot on the film will make a permanent spot.

The machine should also be kept scrupulously clean, and all dirt, dust, film shreds and so forth should be wiped off both before and after using the machine.

Both projecting and condensing lenses should be cleaned with a soft, well-washed linen rag. This should be done every time these lenses show signs of clouding, or show specks. The silvered reflector be-hind the lamp should be kept polished, but should not be rubbed too much.

When setting up for operation, the projector should be run without film to see that all is in proper working order. Observe the take-up and see that it works properly, see that the motor does not heat up unduly. Then look at the light upon the screen. There may be a shadow on some part of the screen, with colored edges. This shadow may be on one side, all around the margin, or a spot in the center. If it is at one side, move the light sideways, until the shadow disappears or is uniform around the screen. If it is at the top or bottom, move the lamp up or down until it disappears or is uniform. If it is uniform move the lamp back and forth until it disappears. These shadows are caused by the lamp being out of focus or out of alignment with the condensors. When the light and operation are all adjusted, stop the machine and insert the film. This is done in various ways, and the manufacturer's instructions should be followed for this operation.

The film is lead from the retort reel in such a manner that when the film is threaded in the intermittent, the emulsion side of the film is toward the light and the image upside down. If this is done, the picture will appear right side up, and the right and left directions will be correct.

If the film breaks, stop the machine, remove the film and pull out about a foot, rethread, fasten the two ends with a small paper clip, taking care that the clip is inserted inside the magazine, so that it will not have to pass through the throat of the magazine. The film can then be patched at some later time.

When the film has been projected, it must be re-wound before it can be projected again. In most projectors it is wound so that the emulsion side is out, and this will lead the film from the top of the retort reel in a straight line into the gate, with the emulsion side toward the light as is proper.

The patching is done just as is explained under the heading "Editing." If any perforations are torn out, this torn place should be carefully trimmed as shown in the illustration on page 170. This will make the film ride smoothly through the intermittent, preventing any further tear, which would occur if the torn perforations were neglected.

If the film is torn, it should be cut in two and patched, the number of frames taken out depending upon the size and shape of the tear. This is illustrated in the accompanying print from a strip of film more plainly than can be described. It is necessary to remove all of the torn portion and to cut the film so that it will match in patching.

If the film should ignite, do not try to extinguish the flame with water. The best thing to do is to throw a blanket or other heavy fabric over the entire machine to exclude all air. If the magazines ignite, there is danger of such a sudden blaze that it is often spoken of as an explosion.

In using new film, the film will often seem to catch momentarily in the gate causing the latter to "chatter." When this occurs stop the machine and remove the film from the gate. A black, waxy substance will be found upon the film rails and this must be removed. Do not scrape the rails with any steel or iron instrument. Operators in theatres usually use a coin, the softer metal removing the accretion of gelatin with-out scratching the rails. If these are scratched, as would be the case if a steel knife were used to remove the gelatin, these scratches would serve to catch it more easily and soon the rails would become so rough that perfect projection would be impossible.

By following these instructions, supplemented by the instructions furnished by the manufacturer of the machine you use you should have no trouble with projection. Projection, as performed in the home, is little more than the intelligent operation of a machine. There is none of the highly specialized technical knowledge required which is required in making the picture or in finishing it. Projection is easily learned by anyone, but I maintain that only the artist will ever make really good photo-plays. However, as all photographic amateurs have more or less artistic sense, these should have no great trouble in cinematography.

If you want to get the most out of cinematography, make the picture yourself, but let Johnny or Mary project it while you watch. The kiddies will keenly enjoy operating a real "movie" machine, and such operation is entirely within the scope of their capability.

Home | More Articles | Email: