International projectionist (Jan-Dec 1936)

December 325183 t^^ INTERNATIONAL PROJECTIONIST PROJECTIONIST With Which is Combined PROJECTION ENGINEERING Edited by James J. Finn Volume 11 DECEMBER 1936 Number 6 Index and Monthly Chat 5 Suprex Arc Magnification Ratio G. S. Patterson 20 Structure and Maintenance of 7 The W. E. 86-Type Amplifier, Jesse A. Cook Unit of the 'Mirrophonic' System , ?,} 1. A. Men Sponsor Projection Aaron Nadell Short Course at University of 11 The W. E. 87-Type Amplifier. . 24 Film Footages, Room Fires, and Aperture Temperatures 12 Letters to the Editor 25 Frank Dudiak The Editorial Page 27 Notes on Cause of Feed-Back . . 15 J. P. Arndt, Jr. News of the Month 28 Fire Prevention Methods in the Notes from the Supply Field . . 34 Motion Picture Industry .... 16 H. Anderson News Notes Technical Hints RCA Raditron Chart 18, 19 Miscellaneous Items Published Monthly by JAMES J. FINN PUBLISHING CORPORATION 580 FIFTH AVENUE, NEW YORK, N. Y. Circulation Manager, Ruth Entracht Subscription Representatives Australia: McGills, 183 Elizabeth St., Melbourne New Zealand: Te Aro Book Depot, Ltd., 64 Courtenay Place Wellington England and Dominions : Wm. Dawson & Sons, Ltd., Pilgrim St., London, E. C. 4. Yearly Subscription: United States and possessions, $2 (two years, $3) ; Canada and foreign countries, $2.50. Single copies, 25 cents. Changes of address should be submitted two 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. Contents copyrighted 1936 by James J. Finn Publishing Corp. International Projectionist is not responsible for personal opinions appearing in signed articles in its columns. MONTHLY CHAT ONLY a month ago I. P. was chronicling the fact, in this space, that it had observed its fifth anniversary without benefit of a special issue, a testimonial banquet or a raft of congratulatory messages spread over several pages. This short, simple statement has resulted in messages from friends and strangers of a number and tone such as to occasion blushes that we really don't do more to earn such praise. The total of these messages would require not several pages but almost an entire issue. To one and all — we thank you. IP. IS running a temperature as a re•sult of certain practices of sound equipment companies in selling their wares by "brand name" instead of by specific unit designation. Read all about it on the editorial page, and be guided accordingly. MORE data on aperture temperature appears herein. After absorbing all this data we can be certain of only one thing — that the flash point of nitrate film is 320° F. Just what happens when the film starts sliding through the projector is a topic which induces a wide difference of opinion. One definite thing is that, irrespective of aperture temperature, nitrate film still should retain the respect of all who handle it. An old friend, H. A. DeVry, in a letter to I. P. suggests the substitution of acetate stock, even though it would cost the industry a bit more for prints. Our own opinion being that the obvious advantages of nitrate film be retained, and that more pressure be exerted on keeping equipment up to snuff and in enforcing those few regulations which serve any useful purpose. ^OME there are who are contemptuous \*Doi projectionist attainment, charging that they are interested only in doing the least work for the most money. Their interest in new and novel products, designed to help do the job better, is nil — so it is said. Yet, within one month I. P. received more than 300 requests for information on a new unit which was allotted a single paragraph of 82 words ! OLD man 1937 promises to be a humdinger in projection circles: the onward rush of color, still more "modern" sound equipment, fundamental changes in projector and stand design, new tubes that will knock the field cold, vastly improved optics (not ready yet, so we can't tell you) — and, did we hear somebody mention television? IP. IS in a recepave mood toward • pictures of interesting projection rooms, to which should be appended data as to size, equipment, the names of the crew and such other data as is considered pertinent.