American cinematographer (Dec 1930)

December, 1930 AMERICAN C I N EMATOCRAPHER Forty-five Progress In the Industry (Continued from Page 43) A report was published the latter part of May, 1930 and a second report in September, 1930 giving the results of extensive tests made on acoustic materials for set construction. Reverberation times were measured with the new materials as against times for an empty room. The greatest absorption coefficient was found with Zonolite plaster brushed 1/16 to Vs inch thick over burlap or chicken wire. A committee made up of representatives from the Board of Fire Underwriters, the New York Bureau of Fire Prevention, and the Motion Picture Producers Association have drawn up a code on studio and laboratory practice, the exchange and the theater. It gives specifications for handling of film from its development to the delivery of finished print. Further information has been published on the Hunter-Pierce de- veloping machine which was mentioned briefly in the previous report. The machine consists of horizontal tanks arranged one above the other with a vacuum system drying compartment on top. It processes 12 separate strands of film simultaneously at the rate of 10 feet per minute and has a capacity of about one million feet of film per week. The film is fed into and taken off the machine from the same end. During processing the film is twisted constantly and is so exposed that any breaks can be repaired very quickly. Lasally has also pub- lished a description of two development machines, those of A. Debrie, Paris, and of Ceyer-Werked A. G., Berlin. The former apparatus is a twin machine, each part of which works independently. The develop- ing and fixing end is located in a dark room, the washing, dyeing and drying end in a light room. Film passes in loops through the various baths at the rate of 1600 ft. per hour. The Geyer machine is of some- what similar design. A slowly growing appreciation of the value of sensitometric control in motion picture film development has been apparent since the advent of the sound motion picture. It is also understood to be a general practice in the larger laboratories to make duplicates of the bulk of negatives as finally edited. A new continuous printer has been designed for sound film records which works at 120 feet per minute. Contact is established by a curved gate with a flattened aperture through which the films are pulled at the correct tension. The printer may also be equipped with an auto- matic light change attachment. A strip of + hin film with perforations on its edges (corresponding to scene changes in the negative) is fed into a special gate attached to the front of the machine. The fibre strip is moved forward at a slower rate than the film and as each hole passes over a contact (of which there are 20) a light change is effected. Changes may be made for scenes as short as 6 inches. It is not necessary to mark the negative in any way by this system. About one-third of the motion picture theatres of the world had been equipped by September, 1930 for sound reproduction of either the synchronous or non-synchronous types. In proportion to the total number of theatres, Canada leads the list of countries with 70 per cent sound installation, the United States is second with 55 per cent, European theatres are rapidly converting their old equipment over for use with sound pictures. The suggestion made by Edgar that projection rooms in major thea- tres will be equipped with extra dummy machines for handling film with sound records only, has been realized in the showing of the fea- ture production “Hell’s Angels” at the Chinese Theatre, Hollywood. Volume with less distortion, elimination of troubles from heating of the film, and a lowering of projector vibration are some of the ad- vantages cited by Edgar. Three dummy projectors connected in parallel were used in the Chinese Theatre demonstration so that two sound tracks could be played at the same time. Six reels of "Magna- scope” film were included in the picture which was projected on a 24 by 37 foot screen and 9 extra loudspeakers were added to the regular installation which consisted of three horns. A special amplifier system was installed to accommodate the 12 horns, which made pos- sible an increase in volume equal to five times the normal volume of the regular sound installation. One of the most interesting innovations in projection equipment of foreign origin is the French Nalpas double projector. Two complete sound-on-film or disk assemblies are mounted compactly on a single rigid support. A resynchronizing device of British origin consists of a footage counter and a dial graduated into 1 6 sections, each of which corresponds to a frame. The device is attached to the 90 foot per minute spindle by a flexible shaft. The footage counter is set to correspond with the edge number on the film and the dial hand is moved to zero. The exact foot and frame passing the aperture can be detected at once, during projection. A power level indicator has been announced for reading the signal amplitude in voice transmission circuits; levels from minus ten to plus thirty-six decibels can be measured. A monitor has been developed to meet the needs for accurate indication of volume levels from power amplifiers in sound reproducing equipment. In a new type of sound-on-film reproducer, mechanical parts in the optical path have been substituted for a cylindrical lens which illuminates only 0.0005 inch of the film area, thus eliminating the usual slit. A new ultra-sensitive vacuum tube has been developed in which the grid current is reduced to a very low value for measure- ments as low as 10-17 amperes. Such a tube will indicate a flow of 63 electrons per second. A new 72 inch dynamic cone speaker and directional baffle has been announced which is claimed to deliver clear, mellow, low frequency 50 cycle sounds and high frequency 7000 cycle sounds. The letters “s,” “f” and “th” can be distinguished clearly. Another type described by Bostwick, utilizes a moving coil piston diaphragm in conjunction with a 2000 cycle cut-off. By using this speaker as an adjunct to the ordinary type, it is claimed that uniform reproduction of sounds from 50 to 11,000 cycles may be obtained. Bull has published data on methods of measuring loud speaker efficiency. Good horn type speakers used in theatre installations are said to have an efficiency of 35 per cent; ordinary commercial speakers only 1 to 6 per cent. At a meeting of the Societe Francaise de Physique, Dundoyer de- scribed a new type of light bulb for sound reproducing equipment. A rectiliear filament is arranged parallel to a flat plate fused in the bulb and a microscope objective used to produce a greatly reduced image of the filament on the film. A projection lamp of novel construction is designed so that the upper part of the bulb is spherical, whereas the lower part narrows to a cylinder, near the base of which is the filament. Methods of using wide-angle lenses to project a much enlarged pic- ture on the screen have been employed in several of the large theatres for certain scenes of such pictures, as “Old Ironsides,” “Trail of Ninety-Eight.” “The Hollywood Review,” and “Hell’s Angels.” In one process, a movable screen was utilized which traveled downstage as the growth of the picture occurred. These methods all tend to over- accentuate the graininess of the picture. The same defect holds if too large a picture is attempted with wide film; tests having shown that width of 50 feet is the maximum permissible before such effects begin to appear. When space is at a premium back stage, the public address system with outlets over the proscenium arch, has been utilized quite success- fully as a substitute for the usual horns during presentation of shorts, such as song cartoons. A novel portable non-intermittent projector for educational use has been made available by Gaumont. It consists of a folding metal case, hinged at the top. Film moves continuously around a hollow sprocket containing a stationary prism. Light from a source on the front of the projector, is directed toward the rear through a condenser system and then through the film, where it strikes the first prism. At this point, it is reflected on to the second prism and thence through the rotating lens drum, and is directed finally through a suitable lens system onto the screen. Several colleges are planning to institute a cultural course on photo play appreciation during 1930-31. Arrangements have been made to release the negatives of outstanding historical pictures made several years ago, for re-editing for educational purposes. To correlate efforts being made in different countries on the pro- duction of educational films. Will Hays has advocated that the International Cinematographic Institute (League of Nations) prepare a statistical record of the demand for such films. Motion pictures will be made from hidden viewpoints of all public events in Vienna in which the police take part; the films will be used later for police instruction. Eighty percent of the workers in a silicate factory in Russia are claimed to have been taught to read by means of sound films. Cottheiner and Jacobsohn have reported on improvements in their technic in x-ray cinematography. In this type of work, the difficulty in the past has been to get sufficient exposure to make pictures with- out over-dosing the patient and working the x-ray tube over its capacity. A new lens of f/1.25 was used constructed of two sphericai cemented elements. A camera equipped with a shutter admitting more light, an improved x-ray tube, a fluorescent screen, and a highly sen- sitive film were employed. With this equipment it was possible to take pictures for as long as 25 seconds at a time whereas 2 to 3 seconds was the maximum exposure which could be used with older apparatus. An International Institute of Television was founded in Brussels, Belgium, which will deal with results of researches in connection with the broadcasting of pictures. Eighteen companies were reported to have twenty-two stations in operation in the United States for tele- vision experimentation. No license is granted by the Federal Radio Commission, however, unless evidence can be shown that the work represents legitimate research. A three-day test made in September, 1930 to transmit televised signals across the Atlantic ocean, failed and was abandoned. A per- manent equipment installation for two-way television was set up in April between the Bell Laboratories and the American Telephone and Telegraph Company’s offices, which are about two miles apart. Television images transmitted by radio were shown as a part of one regular performance at the Proctor Theatre, Schnectady, N. Y., on May 22. A loud speaker system was used to transmit the voices of the actors who performed before a “television camera” at the General Electric plant, about one mile distant. A 48 hole scanning disk covered the subject twenty times per second. Four photoelectric tubes respond 40,000 times per second to the impulses reflected back from the sub- ject. Images were transmitted on a wave length of 140 meters; the voices on 92 meters. At the theatre, the light impulses were reproduced first on a small monitor “teloptikon,” then transferred to a light valve where the light was broken up by a 48 hole scanning disk to reproduce the images which were projected on a screen six feet square set under the proscenium arch. Head and shoulders of the subjects were reproduced in a black and white picture showing gradation of tones. The system was developed under the direction of Alexanderson. Marked progress has also been made in England in ’he develop- ment of television in the hands of Baird Television, Ltd. On |uly 1, 1930 a demonstration of television was made before press representa- tives on a 3 by 6 foot screen. Screen brightness was ensured by using 2100 ordinary metal filament lamps instead of neon tubes and Kerr cells as in earlier experiments. Commutater contact switches, turning on one lamp at a time, sweep the entire bank of 2100 lamps in one-twelfth of a second. The receiving outfit on a portable truck, was installed in the London Coliseum and demonstrated as a part of their regular variety program three times daily from July 28th to August 9th, 1930. A talking film made on Friday, August 8th was televised as a special feature of the program on the closing date of August 9. In another television system, patented by Lieut. Wold of the Quartermaster Corps, U. S. Army, mechanical scanning is said to be rendered unnecessary by the use of a lamp house having a lattice work of filaments, different junctions of which become luminous suc- cessively. According to plans announced during the summer of 1930, positive prints made by the additive Herault Trichrome process have the three successive frames dye tinted. Projection is made with a continsouza- Combes nonintermittent projection which at 24 frames per second is said to suppress flicker. This projector does not use mirrors or prisms, only spherical lenses. The Wolf-Heide process is said to use a similar projection method. Sound prints by the Technicolor process are now made wi h a silver image sound track having a contrast or “gamma” of unit> which is claimed to represent a material advance in the art of reproduction. The (Over)