> > > >

1947-48 Theatre Catalog, 6th Edition, Page 585 (567)

1947-48 Theatre Catalog, 6th Edition
1947-48 Theatre Catalog
1947-48 Theatre Catalog, 6th Edition, Page 585
Page 585

1947-48 Theatre Catalog, 6th Edition, Page 585

THE MAGNIFYING POWER of the special mirror is illustrated by the reHected image of the clasped hands of W. W. Watts (left). vice-president in charge of the Radio Corporation of America's engineering products division. and Col. Nathan Levinson. head of Warner Brothers' studio engineering

remote controls are probably in the proceSS of development, as it, generally speaking, engineeringly possible to operate by remote control any apparatus which can be manually controlled.

The Screen

Should theatre-size television projector be perfected in the near future and adopted into the entertainment scheme of the American cinema, additional problems will be encountered, mainly those concerning the screen.

Under the present circumstances, projection television employs a beaded screen, in contradistinction to the perforated sound screen of general use. Such beaded screens, of course, would necessitate the placement of loudspeakers at the side of the screen during the television portion of the program. The regulation sound screen is not desirable because the television projector is not yet able to throw sufficient illumination to overcome the approximate 15 percent light loss occasioned by the perforations. Accordingly, as television comes to theatres, it will probably be necessary to lower the special beaded screen for the video part of the program.

Since theatre television can be considered to be the logical expansion of research for home-received video-andaudio broadcasting-and the never-ending quest for ways to make pictures bigger and brighterewe may well take a look at what research is developing for screens in the large-picture home receivers.

Directional projection screens, which concentrate the available light into the desired viewing field are an important aid in obtaining adequate brightness. Although various directional screens


have been proposed, the primary consideration has always been how such a screen could be made at a cost to permit its use.

A study of the factors governing the design of projection screens for home receivers was presented last fall to the Optical Society of America by R. R. Law and I. G. Maloff, of the Radio Corporation of America. They described an improved laminated-plastic .screen in which a Fresnel field lens and a multiple-element vertical cylinder lens are embossed on transparent Plexiglas front and rear surfaces. To render the moire effect unobjectionable and provide vertical dispersion a thin Vinylite sheet containing a requisite amount of silica opacifier is interposed between the two transparent sheets. The two sheets of Plexiglas, with the Vinylite sheet be tween them, are bonded in a heated press in a single operation.

The screen provides a brightness gain of 7.5 without perceptible hot spot. In combination with large-aperture reflective optics, it gives a 15-by-20-inch pics ture having highlights with a brightness of more than 50 foot-lamberts, which compares favorably with highlight brightness obtained with direct-viewing kinescopes and more than satisfies the recommendations for good motion-picture-theatre practice.

With progress in screens for largepicture home television sets, it is not illogical to expect that the Law-Maloff researches may be expanded to include screens of sizes usually used in theatreeand the work might be further expanded to include the possibility of developing a screen which could be used for motion pictures and television.

In the event that such a dual-purpose

and technical research statl, on the occasion oi the signing of a cooperative research agreement. The 42-inch mirror developed for the 18 x 24-foot projection television system. weighs 350 pounds. This lens, as part of the television research equipment, was sent to Hollywood under terms of the pact.

screen should come into being, a further problem presents itself: the difference the angle at which television and motion-pictures would be projected. Since the television projector already has a correcting lens, it should not be too severe a problem to design an aspherical correcting lens which would not only correct the image from the spherical mirror but do it in such a manner, adding what additional compensations are needed, that the television images would be perfectly reliected from the picture screen.

The possibility of rear-projection television equipment, with suitable screens, is not to be overlooked, since it is not difficult electronically to reverse position of a television image.


Where television is concerned, the industry quite naturally thinks first of the use of the new medium in connection with theatres. That the same idea obtains in the television industry is apparent in the joint research pacts signed by the Radio Corporation of America with Warner Brothers Pictures, Inc., and 20th Century-Fox Film Corporation last summer. Col. Nathan Levinson will direct the experimental program for Warners at the company's Burbank studios, while Earle l. Spontable will hold a similar 20th Century post for the work to be conducted in the studios of Movietonews, Inc., in mid-town New York.

Both pacts were announced for joint programs of research on large-screen television, and both picture companies have Widespread theatre interests, units of which might easily be equipped to serve as practical laboratories. But the separation of the research locales indi
1947-48 Theatre Catalog, 6th Edition, Page 585