The Bioscope (Jul-Sep 1931)

July 15, 1931 THE BIOSCOPE 1 Technical News and Notes Lighting Control by P.E. Cells The use of the photo cell for the automatic Control of street lighting has now passed the ■experimental stage, and in many areas very promising results have been secured. Lighting ■engineers are now working on the adaptation of the same principle for interior lighting. The lighting of schools, factories, restaurants and cafes is usually left to the discretion of one individual, and forgetfulness, preoccupation or a misguided sense of economy may all result in the lighting-up moment being postponed too long. Yet actually, of course, the precise instant for lighting up ought not to be a matter of taste or preference, but simply one of general illumination, and therefore to be decided with scientific accuracy. Within the last few weeks a device has been developed, based on the use of a photo electric or Selenium cell equipped with an amplifier and subject to light from every direction. This device can be adjusted to turn on the light whenever illumination falls below a pre-determined value. There are limiting conditions for a device of this kind. First, the natural illumination at which the unit turns on the light should at least be equal to and never less than the artificial illumination. Secondly, the natural illumination on the increase of which the unit turns off the artificial light should be, approximately, twice the turn on value. Standard Release Print Changes As a result of recent activities of the Standard Release Print Committee of the Academy of Motion Picture Sciences, an announcement will probably be made during the next few days of considerable importance to every theatre owner and projectionist. The committee is expected to make a decision on a new size for change-over cues, probably making them smaller. A number of test reels have been made up, based on recommendations made by projectionists in response to an Academy questionnaire, and the final decision will be reached after these test films have been •examined. Another technical change expected to emanate from the same source shortly will have to do with the setting up of a new hperture size for cameras. Experts have been at work for months seeking a way to reframe the photographic image so as to absorb the sound track area. The fixing ■of a new aperture size will probably permit producers to build sets on new and more economical lines. Watching the Arc I wonder why so many projectionists put up with amateurish, makeshift methods of watching the arc burning ? Perhaps because they are unaware that a very beautifully constructed crater reflector is produced. It is made by Zeiss Ikon, of Dresden, and distributed by Walturdaw. It can be attached quite easily to the side of the lamphouse and enables the projectionist to focus an erect, and laterally unreversed, image of the crater on any convenient wall or ceiling surface. Some projectionists do this sort of thing with the aid of a small mirror, but few of them ever get a properly focussed image. And until you have studied a properly focussed image of your crater, it is likely you will not be getting the best, or steadiest, results from your arc. The optical system of the Zeiss Ikon reflector is very interesting. In addition to the lenses, two prisms are mounted, one at either end of the tube. The tube is adjustable for focussing, and is eccentrically centred to ensure the correct working of the prisms. The cost — five guineas — may frighten some people, but the reflector will pay for itself. It permits the arc to be studied and adjusted in a manner which is otherwise quite impossible. The saving in carbons, and improved screen results from better illumination, may surprise those whose methods of arc feeding are at present of the happy-go-lucky, hit-or-miss, order. Colour Photography Unsatisfactory It is a curious commentary on the many colour systems in existence that none of them quite measure up to the needs of scientific recording. A recent expedition to Africa has been endeavouring to get the WHEN YOU WANT A CHANGE TO REAL GOOD WORK.' FOR HAND-PAINTED POSTERS, BANNERS, SHOWCARDS AND DISPLAYS OF QUALITY, TRY: CINEMA ADVERTISING SERVICE 6,, MAIDEN LANE, LONDON, W.C.2. Telephone: TEMPLE BAR 5660. Let us quote you and be assured of prompt delivery and attention. colours of the Ruwenzori Range in the Belgian Congo — the most important range of mountains on the African continent. The question of what colour process should be used was fully discussed, and it was finally decided that colour notes, taken on the spot and afterwards translated by painting the slide, would furnish results superior to any process of colour photography. The method pursued was this. Immediately the photograph was taken, very full and careful notes were made both by description and by matching as many colours as possible. The colour notes for a single photograph often ran to several hundred words and the results, though looking rather unnatural, are declared to be a faithful representation. European Patrons More Critical of Sound M. C. Batsel, chief engineer to R.C.A, Photophone, has just returned to the States from a long European visit. He has expressed the opinion that patrons of motion picture theatres in England, France and Italy are much more particular about the quality of sound reproduction than are patrons of theatres in the United States. Europeans have become sound conscious, he says, and as a result inferior apparatus is being replaced. Modern Precision Limits Bell <fe Howell manufacturing precision is maintained at a very high standard. Certain parts of their camera equipment are held to a tolerance of 1 /10,000th of an inch. Inspectors see that no lapses in tolerance are permitted in these or other instances. A Filmo 70 Camera, for example, is inspected over 2,500 times during its manufacture. Intensive efforts are made to bring the individual worker to recognise the importance of accuracy by educational methods, the stimulation of individual and departmental pride and continuous inspections. Encouraging Manager Initiative There is another agitation in America at the moment against the principles of circuit operation. Harold B. Franklin is only one of a number of leading American executives who are setting themselves against the dangers of centralised control. Theoretically, it is said there is nothing wrong with circuit theatre operation, but actually the system proves entirely wrong, killing individualism and showman personality. In an effort to stimulate individual enterprise at the present moment, R.K.O. is offering a free vacation to Europe and a ten-day stay here, with all expenses paid, to the theatre manager whose box-office shows the biggest increase for J uly. A plan of campaign has been outlined for the managers competing for the Honour Award. A similar scheme in this country would be enormously popular and would doubtless in the end prove profitable to the company bold and generous enough to initiate it.