International projectionist (Jan 1959-Dec 1960)

HSR S3 I95§ INTERNATIONAL PROJECTIONIST Including a special Audio-Visual section relating to the operation and maintenance of A-V equipment in the educational and industrial fields. R. ENTRACHT, Publisher Volume 34 JAMES J. FINN, Editor R. A. MITCHELL, Contributing Editor MARCrY 1959 Number 3 Index and Monthly Chat 3 Cinemascope: Keynote of Modern Projection .... 5 The Carbon Arc for 16-mm Projection 3 R. B. Dull Projection Pot-Pourri: Light Source, Image Ratios, Film Sizes, Screens 11 J. B. Stableford The Geneva Intermittent Movement: Its Construction and Action 12 A. C. SCHROEDER Viewing the Projector as an Integral OpticalMechanical System 13 Harold E. Rosenberger Audio-Visual Section 14-20 A-V Education: A New Era Dawns; StudsntPrepared "Opaques'* a Great Aid; Observe Your Oiling Instructions; Using Closed-Circuit TV in Education; Sound versus Noise; Stereo: What it is and What it Does; Items. Obituaries 21 "Why Exhibitors Steal" 22 News Notes — Technical Hints — Miscellaneous Items INTERNATIONAL PROJECTIONIST, published monthly by the International Projectionist Publishing Co., Inc., 19 West 44 Street, New York 36, R. A. Entracht, President. Telephone: MUrray Hill 2-2948. Subscription Representatives: AUSTRALIA— McGills, 183 Elizabeth St., Melbourne; NEW ZEALAND — Te Aro Book Depot, Ltd., 64 Courtnay Place, Wellington; ENGLAND and ELSEWHERE— Wm. Dawson & Sons, Ltd., Macklin St., London, W. C. 2. Subscription Rates: United States, Canada, and U. S. Possessions, $3.00 per year (12 issues) and $5.00 for two years (24 issues). Foreign countries: $4.00 per year and $7.00 for two years. Changes of address should be submitted four weeks in advance of publication date to insure receipt of current issue. Entered as second-class matter February 8, 1932, at the Post Office at New York, N. Y., under the act of March 3, 1879. INTERNATIONAL PROJECTIONIST assumes no responsibility for personal opinions appearing in signed articles, or for unsolicited articles. Entire contents copyrighted/ 1959 by INTERNATIONAL PROJECTIONIST PUBLISHING CO., INC, j 420 Wto/dhly Chcd Film Buckle Still Prime Problem PRIME projection problem still is the out-of-focus screen image, as common in four-wall theatres as it is at driveins, although the latter are so desperately in need of more screen light that they risk ruining mirrors, the mechanism itself and the film print by over-amperaging the arclamp. Out-of-focus screen images are induced automatically. Wider screens of themselves require stiff amperage levels, and the latest color films, while providing richer color rendition, have a greater degree of opacity than previous such releases. Energy is released from a burning arc in the form of waves of different lengths and properties. A percentage of these are light waves in the region of the spectrum visible to the human eye. The remainder manifest themselves as heat without raising the level of illumination. For projection purposes, the ideal would be to eliminate all heat, since it contributes nothing to the efficiency of the system. But this is not possible, since the visible light waves themselves are also a source of heat. The only practicable solution, then, is to remove from the system those waves which do not add to illumination. Silvered Reflector with Filter Silvered reflectors focus the total energy released by the arc (with some slight loss) on the film gate. A heat-reflecting filter, inserted in the system between reflector and gate, prevents temperatures at the gate from becoming dangerously high. The limit of temperature control possible with this method, however, may not be adequate for the needs of the larger indoor theatres and for drive-ins. The solution that immediately presented itself was to increase the efficiency of the heat filter. But filters have certain disadvantages: (1) their use entails a certain degree of light loss; (2) if the filter is to serve its intended purpose, all energy from the arc must pass through it. Where high amperages are used, this often results in burning out the center of the filter, particularly where the beam from the arc is focused down to less than the full diameter; (3) it if another element to be cleaned and maintained. The answer, then, was to eliminate the filter. This has now been done in the form of the "Balcold Reflector," developed by Bausch & Lomb Optical Co.. which differentiates between visible light and heat. Elliptical in shape, its second surface is coated with a combination of low and high-index materials — visible light is reflected back to the film gats, heat passes through. New Reflector Much More Efficient Substantially more efficient in reducing heat than the silvered reflector-filter combination, the BALcold permits the use of higher levels of illumination with far less danger of film buckle — even of "green" film. This is especially true for high-speed and short-focus lenses with critical focusing. Also, it assures longer life for projector parts. Whether because of ignorance of its existence or for reasons of "economy", exhibitors have purchased far too few of these reflectors. In the interest of an improved screen image no less than that he has lived with the aforementioned tribulations, the projectionist should explain the advantages of and keep urging the purchase of this BALcold reflector. —J. J. F. INTERNATIONAL PROJECTIONIST • MARCH 1959