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1954-55 Theatre Catalog, 12th Edition, Page 276 (240)

1954-55 Theatre Catalog, 12th Edition
1954-55 Theatre Catalog
1954-55 Theatre Catalog, 12th Edition, Page 276
Page 276

1954-55 Theatre Catalog, 12th Edition, Page 276

of. approximately 1.4, the non-anamorphic VistaVision picture width could be 89 feet, the anamorphic VistaVision 102 feet, the CinemaScope optical picture 122 feet, and the CinemaScope magnetic track picture 133 feet in width, which incidentally, is about the maximum size that is being used in present day drive-ins.

The accompanying chart shows these various figures for the different types of projection systems and different types of screens. All the figures shown are based on the use of the most powerful projection arc lamp available today and the sizes of the screen are calculated so that a brightness of four foot lamberts will be obtained in the center of the screen when the shutter is running. This figure of four foot lamberts is a little bit above the average brightness we find in most drive-in theatres today.

Screen Widths

To explain how these screen widths have been arrived at, take, for example, the magnetic track CinemaScope system which is calculated to have a 133 foot width for four foot lamberts center brightness.

IN ORDER to get a properly lighted picture on huge drive-in screens. such as the one at the Westbury, Westbury. Long Island, there are many factors

When the center brightneSS on a screen is four foot lamberts, and with the typical distribution pattern, the average brightness over the whole surface of the screen is found by test to be 2.9 foot lamberts.

With a screen having a reHective face tor of 1.4 it is only necessary to project 2.05 foot candles to the screen to realize the 2.9 foot lamberts brightness. The 31,000 lumens which this powerful lamp can deliver through a CinemaScope aperture and standard f2.0 optics is reduced by the 50 per cent shutter loss and the eight per cent lens loss so that the incident light on the screen is 14,350 lumens.

Therefore, since lumens are the product of average foot candles times screen area, we obtain the area that we can illuminate to this 2.05 foot candles intensity by dividing 14,350 by 2.05 for a resulting screen area of 7000 square feet. The picture width can be computed by taking the square root of the product of screen area times screen aspect ratio, which in the example calculates to 133 feet wide. The other calculations in the chart were made in a similar manner for the other projection systems and screens.

Assuming any particular theatre to have ample screen illumination on a

matte screen using standard size aperture, the screen width that can be illuminated to the same brightness for any of the wide screen systems can be calculated by multiplying the present screen Width by the uwidth ratio factor" given in the last column of the chart.

For example, if your own theatre presently has a 50 foot wide picture with standard projection on a white screen, and you wish to determine the width of matte white screen that can be illuminated to the present level of brightness with the VistaVision anamorphic system, simply take the present standard picture width and multiply it by the ttwidth factor ratio" of 1.18 from the chart. The resultant width in this example would be 59 feet.

The illusion of living presence, the sole advantage of all the new screen techniques, can only be realized with an increase of screen width of from 1.75 to 2 times over that heretofore employed for standard projection.

Accordingly it is readily evident that most theatres will require the most modern and powerful projection arcs in order to meet the requirements of a sufiiciently increased screen width for proper presentation of all wide screen techniques.

which must be taken into consideration. An important thin to be conSIdered is how the screen is faced, as different materials give di erent results.

1954-55 Theatre Catalog, 12th Edition, Page 276