Exhibitors Herald (1927)

October 1, 1927 EXHIBITORS HERALD 53 Digest of S. M. P. E. Addresses ( Continued from page 51) A COMPACT MOTION PICTURE DENSITOMETER By J. 0. Capstaff and R. A. Purdy A description of a portable and relatively inexpensive instrument for the measurement of small areas of density or relative blacknesses of photographic images. The apparatus is useful particularly for the determination of the printing characteristics and the photographic quality of motion picture negative or positive images. Its adoption will assist greatly in the control and production of better quality motion pictures. * * * A TRIAL AND ERROR METHOD OF PREPARING A MOTION PICTURE SENSITOMETER TABLET By C. E. Ives and J. P. Crabtree A sensitometer is an instrument for determining the correct exposure when printing a positive film from negatives. With one type of this instrument a series of increasing expostures are impressed upon the negative through a sensitometer tablet, which consists of a series of areas of the same size as a motion picture frame and of such densities that the light transmitted by them is proportional to the intensity of the various light change steps on the printer. Previously it has only been possible to prepare such a sensitometer tablet with the aid of precision instruments. The above paper gives instructions for constructing such a tablet by trial and error methods. * * * THE LUBRICATION OF MOTION PICTURE FILM By J. I. Crabtree and C. E. Ives It is necessary to apply some sort of lubricant to the surface of motion picture film in order to facilitate its passage through the projector. If this is not done an accumulation of hardened gelatin forms on the projector gate and the friction which results often entirely arrests the progress of the film. Present lubricating practice consists in applying a thin line of wax along each edge of the film. This is satisfactory, but there is a tendency to apply too much wax, which encroaches on the picture area and causes spots and blotchiness on the screen. Also the presence of too much wax in the gate is apt to cement the film to the aperture plate if the projector is threaded when warm and then allowed to cool, so that on starting the projector the film remains stationary in the gate and is apt to catch fire. The above objections have been overcome by applying a solution of wax dissolved in carbon tetrachloride to the entire surface of the film and then buffing this. The result is to impart a high polish to the film surface analogous to that on polished footwear. This treatment insures sufficient lubrication and film so treated is impervious to the effect of oil, so that the trouble from patchiness and blotches on the screen caused by oils is eliminated. * * * “NARROW-CASTING” By John B. Taylor While there is much truth in the old saying, “There is nothing new under the sun,” it often happens that an idea or a device is tried and discarded or remains dormant for a number of year. After a time conditions change, new needs arise, difficulties and limitations disappear in the progress of events. Then the old idea is brought forth again in new clothes to be acclaimed by those to whom it appears new and strange, and to be belittled by some who have read that So-and-So did about the same thing years before. The demonstration of “narrow-casting” which has been arranged for your edification is old in the broad sense, but new (since many have not seen it), and new also in some details and in the employment of devices not available a half century ago when Bell and Tainter were experimenting with their photophone. Bell and Tainter sent articulate speech a distance of several hundred yards over a beam of light. A powerful source of light was required — sunlight or electric arc ; the diaphragm employed was of a size and tension to be deflected considerably under the fairly powerful tones of closely directed voice. Motion of the diaphragm either changed the direction of a reflected beam of light or moved some form of shutter to change the intensity of the beam. Their receiver, or arrangement for translating from light back to sound, was a large reflector with selenium cell at the focus and a battery connected in circuit with the selenium cell and telephone to be held to the ear. With this old apparatus, quality of speech or tone from musical instruments would probably not compare favorably with present day phonographs and radio loudspeakers. In constructing a photophone at the present day for carrying speech or music, we have available several electrical devices with improvements unknown to Bell and Tainter at the time of their early experiments. Perhaps the most important of these are “radiotrons”(or vacuum tube amplifiers), photo-electric cells, oscillograph (or high frequency galvanometer), and gasfilled tungsten filament incandescent lamps. Utilization of these modern amplifying devices in a photophone permits the feeble energy in a small beam of light to be increased sufficiently to give any desired amount of power for actuating a loudspeaker. Similar amplifiers may be utilized at the transmitting and to enable soundcollecting devices to move mirrors or actuate other arrangements for controlling the light beam. The photo-electric cell responds faithfully to extremely rapid changes of light and consequently does not introduce distortion in the quality of music or give unnaturalness to the spoken voice. While the tungsten incandescent lamp does not have the brilliancy of the electric arc, the greater simplicity, steadiness and ability to operate on a few cells of battery adds greatly to convenience, simplicity and portability which are highly desirable in some applications of the photophone principle. The demonstration of music in a beam Exhibitor Gets Plenty of Publicity for House ( Special to the Herald ) SCOTTSBORO, ALA., Sept. 27. — Claud T. Bobo, of the Dreamland theatre has succeeded in getting the greatest possible amount of publicity out of the fact that he is building a new theatre. In the course of moving the old theatre from the lot, it stuck right in the middle of the street and blocked traffic for a week. Naturally everyone in the county learned that Bobo is building a new theatre. Meantime Bobo obtained permission to operate the theatre in the middle of the street, and then came more publicity. His new theatre will seat 700 people. or pencil of directed light has been called “narrow-casting” in order to invite comparison and contrast with the parallel art of broadcasting. * * * OIL SPOTS ON MOTION PICTURE FILMS By G. E. Matthews and J. I. Crabtree The presence of oil on motion picture film previous to development or during drying produces spots or markings on the processed film having the general shape of the globules or smears of oil. The appearance of the markings produced is independent of the nature of the emulsion or the kind of oil commonly used on cameras, printers or processing machines. The spots are more pronounced if film is exposed after it is coated with oil, because the oil spot acts as a negative. The manipulative treatment which the film receives and the time elapsing after access of the oil and previous to processing greatly influences the appearance of the markings. In the case of unexposed film certain types of oil produce a fogging effect and cause dark markings if left on the film several weeks, but with exposed film the oil acts as a resistance during development and produces a spot or patch of lighter density than the surrounding area. Also, since a greasy emulsion surface has a high propensity to accumulate airbells on immersion in a developer, many oil spots have circular white centers caused by the protective action of such airbells. By gently brushing the surface of the film during the initial stages of development, the airbells may be dislodged, but this is only possible when film is developed on a continuous processing machine. A classification of various markings is given. The most satisfactory method of eliminating oil from the surface of motion picture film and therefore of preventing the formation of oil spots is to immerse the film in a bath of benzene or carbon tetrachloride, squeegee and dry thoroughly previous to exposure and development. Suggestions are included on methods of lubrication of machinery for handling motion picture films. * Jfc MICRO CINEMA IN MEDICAL RESEARCH By Heinz Rosenberger The motion picture is found again in the vanguard of scientific research. In the hands of skillful microscopists motion pictures are revealing the nature and habits of those living bodies which are too small to be seen by the naked eye. By its domination of time it is possible to slow down a change or a movement which is otherwise too rapid for us to study or to speed up a series of seemingly meaningless slow motions into an understandable activity. By such means as these the secrets of nature are being unfolded and the causes and prevention of disease are being learned. The adaptability of motion picture records for exhibition to large groups of people makes them unique in their usefulness for research and educational purposes. Hey woodWakefield Company THEATRE SEATS Detroit Hockey Club, Detroit, Mich. E. D. Smith’s theatre, Salt Lake City, Utah. J. J. & Lee Shubert, “Pitt” theatre, Pittsburgh, Pa., and their Philadelphia theatre. Schine’s Ohio theatre, Lima, Ohio. Riverside theatre, Medford, Mass. Stowel Mayen theatre, Los Angeles, Cal. Genessee Clayton theatre, Waukegan, 111, Sunset theatre, Tacoma, Wash. Bellerose theatre, Bellerose, L. L