Moving Picture World (Nov-Dec 1927)

MOVING PICTURE WORLD 45 F. H. Richardson's Better PROJECTION “ Better Projection Pays” At Your Box Office Projection Data Sought WM. L. ZWIGARD, Mgr. Borinquen Park, San Juan, Porto Rico proposes erecting a new theatre building, the auditorium of which will be ioo' wide by 70' long. From a sketch, undimensioned except as above, I presume the seating will be approximately 62 feet wide. Says he has had a Fourth Edition Bluebook for five years. Wants to know what size the screen should be to project 86 feet. Will use two Simplex projectors and a 7J/2 H. P. motor generator set. Wants to know what I would suggest as to lenses. Wants to know ideal height for both screen and projection room, height of screen center above stage floor, height of stage floor above auditorium floor and correct slope for auditorium floor, considering the fact that the walls will be only 17' high. First of all, the information supplied tells me very little of value in giving answers. Projection distance alone means nothing at all, insofar as concerns advising about lenses. I would suggest that the EXACT projection distance (lens to screen surface), the type of light source (whether straight D C arc, high intensity arc, reflector arc, high intensity reflector arc or Mazda) which will be used be determined, and the EXACT width of picture be fixed upon. Send ALL this data to the Bausch & Lomb Optical Co., Rochester, N. Y., asking that complete optical trains suitable for the work be sent you. That is the LOGICAL way to get just what is needed. However if you send this data to me I can tell you what is needed. As to size of picture, your conditions as set forth will make the use of a screen of wide diffusive powers imperative, and that in turn sets up a condition which demands a pretty strong light. A large picture would require a great deal more light than a small one, illumination per unit area being equal. I do not know what your audiences are accustomed to, but in my opinion you will get the best results with a picture not smaller than 12 feet and not larger than 14 feet wide. Personally, were it my own theatre, I would select the 12 foot picture, especially if your films are old and have lots of “rain”. As to height of projection room and height of picture above stage floor, there won’t be much leeway, since your total height is limited to 1/, probably four of which is taken up by stage height, and surely not less than 18" by the borders — you say nothing about having a stage loft. A picture 14' wide will be, if undistorted by projection angle, 10' 6" high,, and when you take 4 plus ijZ feet equals 5 J4 from 18 and your picture is itself 10' 6" high you can see where you are at. Under the conditions I think you had better place the 'picture top so it will just clear the borders. As to stage height and slope of floor — well, I am sorry to say that is out of my field. Better consult an architect though I would think, from my limited knowledge, that about four feet would be right for the stage floor height, and that one foot of rise in ten would serve very well for the auditorium floor. I think the latter is about what is usually used. Incidentally, your accompanying sketch shows the projection room to be 15' wide by 6' front to back, which is bad. The fifteen wide may be and probably is all right, but it should be at least 8' front to back. Why cramp your projectionist in his work when you have ample space available. Certainly you should add two or three feet to the six shown. It will cost you relatively very little more and be infinitely better. Oh yes, draw an “elevation” (sectional view) of the auditorium, to scale, with stage floor in place and floor slope line drawn. Then so locate your projection room that the lower side of the light beam will be jl/2' above the floor at its closest point thereto. That will be your correct or best lens height above the auditorium floor. Projects The Water THE show at the Roxy Theatre this week reveals another of the wonders that go to make up “The Cathedral of the Motion Picture”. In the Woodland Fantasy scene the ballet dances before a moving waterfall in a deep glen. The effect is achieved by use of a rear projection machine, the only one in the world. The stage of the Roxy is in the shape of a triangle, so that the back corner is a distance of sixty feet from the last scene drop. A special screen, called the translux, is put in place, and the back projection machine plays on it, with the image visible to. the audience on the other side. Bluebook School Answers 601 and 602 Note. — This “School” is designed to arouse interest in the study of those many problems which contantly arise in motion picture projection, AND to cause men to really study the Bluebook and assimilate the vast amount of knowledge contained within its covers. Question No. 601. — In your opinion, how often should the electrical part of the projection equipment be tested for grounds? W. C. Budge, Brooklyn, N. Y. ; C. H. Hanover, Burlington, la. ; G. L. Doe, John Doe. “Bill” Doe, Doughy Doe and I’m A. Doe, all Chicago, Ills. ; George Lawrence, Sackville, N. B. ; D. G. Henderson, Quincy, Ills. ; T. R. Roand, St. Louis, Mo. ; T. R. Bankerton, Wentzville, Mo.; Allan Gengenbeck, New Orleans, Bluebook Question Question No. 620. — Should the intermittent sprocket be so adjusted that it has no perceptible circumferential movement. Tell us how you yourself decide when the movement is sufficiently closely adjusted. La.; A. L. Tompkins, Ft. Worth, Texas; T. D. Alexander, Decatur, Ills. ; A1 Lehman, Glenside, Pa. ; Chas. E. Curie, Chattanooga, Tenn. ; T. Y. Fullerton, Des Moines, la. ; Frank Duduak, Fairmont, W. Va. ; H. L. Baker, Johnstown, Pa. ; M. D. Peters, San Francisco, Calif. ; Chas. Hall, Spokane, Wash’n. ; W. Turner, Pontiac, Mich. ; A. D. Plenley, Seattle, Wash’n. ; N. R. Quigley, Oklahoma City, Okla. ; W. J. Lathrop, Little Rock, Ark. ; T. D. Arabel, Philadelphia, Pa. ; Frank T. Spencer, Little Rock, Ark.; Albert Hancock, Dallas, Texas; John Reilly, Boston, Mass.; Thomas Billings, London, England; and W. C. Burke, Topeka, Kas., all sent in satisfactory replies to this one. The answer of brother Hanover is selected for publication. It differs little, except in phraseology, from several others. Hanover says : “A ground may or may not mean loss of power in appreciable degree, but in any event it sets up a bad condition, hence should not be permitted to exist. If a permanent testing lamp, such as is described on