The motion picture almanac (1931)

382 The MOTION PICTURE ALMANAC 1931 (Continued from page 379) on film and the introduction of methods of minimizing ground noise, whereas disk recording affords little opportunity for further reduction in surface noise. A selenium cell designed by Thirring, a condenser type, is used in the Selenophone process as the light sensitive element. The company has developed a method of recording on paper for use with amateur equipment. According to a report from India, sound pictures are becoming increasingly popular especially since recording equipment has become available. Three companies have recording equipment, and the first all Indian feature picture scheduled for release in March was recorded in Hindustani. This creates a precedent and if followed will be a tremendous step forward in solving the vexed question of one language for the country instead of the 300 odd dialects at present used. Thin unbleached muslin cloth, properly stretched, does away with reverberation almost entirely on motion picture sets and permits much greater flexibility in sound recording. It is often possible, with such sets, to take medium and close-up camera shots simultaneously, using only one sound pickup. A set made entirely of cloth is a rarity but it is not uncommon to make them 75 per cent of cloth. A Laboratory Practice. — Since the advent of the sound picture, the technic of laboratory processing has improved considerably. The significance of sensitometry in relation to sound and picture quality is being realized more and more each year. Recent processes of ground noise reduction demand an even higher laboratory precision in film development. In the field of sensitometry there has been a tendency to concentrate on time scale devices rather than on intensity scale instruments. There is a need, however, for standardization on a particular type of instrument so that comparisons between controls at the various studios could easily be made. Problems facing laboratories are (1) a means of measuring quickly the developing activity of a bath or the gamma to which the film is being developed, (2) a method of maintaining the bromide concentration constant throughout the life of the solution and recovering this salt from the bath, and (3) a non-staining developer for the development of variable density sound film. An investigation has been started by a special sub-committee of the Academy of Motion Picture Arts and Sciences relative to methods and standards in film processing. Formal recognition will be given desirable standards to which there is general agreement. Light valve recording on the underexposure or "toe" portion of the characteristic curve is stated by Lewin to be in use by Paramount for scoring and playbacks. Goldschmidt has described a photometer for calibrating printing lamps which employs a photocell and a precision torsion galvanometer, reading directly in lux. For printing "stills" in a German laboratory, a semi-automatic device is used. Two graduated filters may be moved simultaneously, one over the printing light and the other over a comparison lamp of fixed intensity. A photometer which compares the extreme densities on the negative indicates the contrast grade of paper required. A growing demand exists for the inspection of every release print for sound and picture quality. One type of film inspection equipment consists of a standard Western Electric reproducer set installed on a projector. Sound is picked up by a caesium cell and fed into an amplifier, having an out-put ample for headset monitoring, or with additional amplification, standard theatre horns may be used. A sound head made by Vinten is being used in England for the examination of release print quality. A General Projection Equipment and Practice.— Practically an instantaneous change of lenses was stated to be possible with a new front plate assembly for the Powers projector. Other modifications are a lens centering device, a micrometer focussing pinion, a framing lamp, and an aperature change assembly. The shutter on the German Bauer M-7 projector is now arranged in front of the condenser lens in accordance with recent projector construction practice. The use of separate projectors for reproducing the sound was initiated in a London theatre, the Pavilion, in November, 1930. For preview service, in Hollywood, one company has provided two portable dummy sound projectors. These are installed in the theatre and coupled to the regular projector before the preview. This permits the studio to have a preview of any production using the assembled intercut prints of both picture and sound track and it eliminates the necessity of making a sound print which usually requires cutting after the preview. Sound reproducing equipment is being manufactured by a British firm which use a magnetic coupling between the projector and the turntable. A single photoelectric cell is placed centrally between two projectors. On the Friess sound projector, the starting of the projector and fading is accomplished automatically by means of the film strip itself. The film is inserted in the projector for a change-over without regard to synchronization. Metallic contacts on the film then actuate relays successively which lower the needle into the proper groove, close the fader circuit, and extinguish the light in the first projector. In the Projectophone devised by Mihaly the sound track image is projected by a suitable optical system onto a caesium photocell located at some distance from the projector. If the detector is located at one side of the main projection screen, it obviates the need of wiring between the projection booth and the screen. A shallow type horn has been introduced by the Western Electric Company, which is provided with twin air columns meeting in a common mouthpiece. The equipment is 26 inches deep, 107 inches wide, and 62 inches high. Changes in sound reproduction caused by varying slit width have been considered by von Hartel. Besides presenting mathematical formulas concerning the sound intensity variations as the slit is gradually widened, the paper gives data showing that halation causes overtones which consist especially of octaves. Frediani avoids the use of photocells in sound reproduction of variable density records by passing them between electric contacts connected with the grid circuit of a thermionic amplifier. For such reproduction, paper prints may be used. A Projector Lenses, Shutters, and Light Sources. — The recent use of screen pictures of large size has led to the development of lens turrets on projectors with objectives of the desired focal length ready to be moved into position to suit the requirements of the program. The demand for higher powered light sources in the theatres using low intensity reflecting arc lamps has been met by the production of a higher amperage trim. It is designed for 32 to 42 amperes at the arc. Previously, 32 amperes at the arc was the highest attainable. The introduction of a pre-cratered high intensity projector carbon was also noted. A Special Projection Equipment. — Two new types of portable continuous projectors have been marketed, one for 35 mm. film and the other for 16mm. film. Approximately 400 feet of sound film can be accommodated on the 35 mm. projector. Considerable research has been conducted by Ives to devise cameras and projectors for the production of pictures showing relief. The method consists, essentially, of making a series of pictures from juxtaposed points around an object and projecting the prints from these onto a special screen. Two types of screens having these properties have been developed, one made of vertical solid celluloid rods, and the other of strips of mirror. More recently a stationary camera requiring only a single exposure has been devised but Ives considers that much research is considered necessary to perfect the process. Three new types of screen have been described in the literature as being available commercially. A non-inflammable screen of rubber composition perforated with small holes was demonstrated in November in London. Another type of screen incorporates a cooling system for the theatre. Behind the metal screen surface is located a refrigerating plant which causes the screen to become entirely coated with white frost. In the third type, a non-glare and pseudo relief principle is introduced. A Theatre Acoustics and Construction. — From experience to date, it would appear that the most satisfactory results from the standpoint of sound reproduction are obtained in theatres having a maximum seating capacity of not over 2,000 seats. In theatres of much larger seating capacity, the sound quality suffers considerably when the auditorium is only partially filled, whereas in the smaller theatres this condition is not as serious. A chain of midget motion picture houses is being planned for operation throughout the United States. The seating capacity will average about 200 and the shows will be of varying length from 15 minutes to 1 hour. In connection with the statement that about 55 per cent of the 22,7 31 theatres of the United States are now wired for sound, it is of interest to learn that the Opera of Malta, which has remained practically unchanged since it was built 200 years ago, has recently been wired for the showing of sound pictures. According to a U. S. Government Bureau report, acoustic problems in Brazilian theatres are very difficult of solution. Walls are made of concrete or stucco and seats of plain wood. It is extremely difficult to use drapes as the insects attack most materials used. A Applications of Motion Pictures. — Production of sound pictures has been initiated by the U. S. Agriculture Department in its own studio in Washington. One of the first pictures scheduled is the Indian sign language film which is being made for the U. S. Department of the Interior. Sound pictures are receiving attention in England. In December 800 educational associations were called into conference at Burlington House to consider the value of (Continued on pane i84)