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1954-55 Theatre Catalog, 12th Edition, Page 327 (291)

1954-55 Theatre Catalog, 12th Edition
1954-55 Theatre Catalog
1954-55 Theatre Catalog, 12th Edition, Page 327
Page 327

1954-55 Theatre Catalog, 12th Edition, Page 327

'A Lamp for the New Dimensions

A Description of the National Excelite Projection Arc Lamp and Its New Design to Meet Demand for More Light

BRIEF: Regardless of whether it was three-dimensional films . . . CinemaScope

. VistaVision . . . or any other new projection process . . . all of the newly developed and perfected techniques have demanded one thing . . . and this was more light on the screen . . . This need for greater screen illumination was an important one . . . The theatre industry has been fortunate in that the manufacturers and dealers who service the theatres have always been able to come up with the answer to any major problem . . . and this case has been no exception.

This article gives a complete description of the new National Excelite proiection arc lan'p . . . The new construction features are explained . . . and the reasons for any changes and innovations are put down in a manner that any theatre operator will be able to follow . . . The subject of carbons . . . reflectors . . . operation of the lamp . . . and maintenance are also given thorough attention.

The several new types of projection systems which have been accorded quite general adoption have introduced the need for a wider range of screen illumination than was necessary with practices common for so many years.



Vica-prvsidnnt. National T/mmrv Supply

In many cases it is practical, even necessary, for a theatre to have a light output of 15,000 to 17,000 lumens for a particular type of screen presentation one night, whereas the following night there may be needed 26,000 lumens for a different type of presentation.

All things being equal, when projecting a 2-1 aspect ratio with the widescreen type of presentation wherein the short focal length lenses are used, there is required approximately 45 per cent more illumination than with the old standard 1.33 to 1 aspect ratio.

The efficiencies of the CinemaScope system are such that the light require ments over and above the old type of standard projection are not particularly excessive. However, in view of the fact that the single film type of 3-D presentations are coming into some favor, due to the increased excellence from a technological standpoint, the amount of ile lumination has to be appreciably increased over and above that required

THE EXCELITE projection arc lamp has been so designed that it is capable of supplying light necessary to properly show the new dimensions.

for CinemaScope or VistaVision or the other wide-screen techniques.

Carbons Improved

There has been made available within the last year two new carbons for use in rotating feed reflector-type projection arc lamps, the 11 mm. regular type and the 10 mm. Hitex type. They have enabled gains in screen illumination of up to 30 per cent over that which was obtained with the 9 mm. and 10 mm. regular carbons, extending the range of lumens that can be supplied from 15,000-21,000 to an overall range of between 16.000 and 26,000 lumens.

The Excelite lamp, due to the foresight of the manufacturer, was designed with built-in interchangeability features, so that slight modification permits taking full advantage of these late carbon developments. Excelite type lamps being the type which permits this easy interchangeability without sending the lamp to the factory for rebuilding, have naturally come into very Wide use. Provisions have been made whereby Excelite lamps can be quickly converted to meet the various modes of modern day presentation. Only four components need be changed to accomplish the various switches.

L in MN .
1954-55 Theatre Catalog, 12th Edition, Page 327