The Projection of Lenticular Color-Films

In the projection of lenticular color-films a large portion of the incident light is lost by absorption in the tricolor filters. To determine the feasibility of satisfactorily showing these films in large theaters, an experimental projector was set up embodying the few simple changes in standard theater equipment that were necessary to obtain the required large increase in screen illumination. — Successful demonstrations with the apparatus at Loew's Rochester Theater at Rochester and the Center Theater at New York have proved that it is quite possible to secure enough screen brightness to give a satisfactory showing of the lenticular films in the majority of theaters. — The principal changes made in the standard projection apparatus in order to obtain the greatly increased illumination were as follows: (1) Increased Relative Aperture.—By substituting an f/1.6 projection lens for the f/2.4 lens commonly used, and by increasing the working relative aperture of the 65-ampere high-intensity reflector arc so as to take full advantage of the increased aperture of the projection lens, it was possible to get 2.25 times the screen illumination obtained with the regular equipment. (2) Reduction of Shutter Loss.—A further increase was obtained by the use of a quicker pull-down and a corresponding reduction in the angle of the shutter blades; this may not, however, be feasible in practice. (3) Increased Filter Transmission.—As a result of numerous practical tests it was found to be possible to increase the transmission of the tricolor projection filters by 33 per cent, without undue loss of color values. (4) Lower Print Density.—The excellent tone reproduction obtained in the process, together with a modification of the optics of the lenticular film, makes possible a substantial lowering of the print density. The resultant increase in the brightness of the projected image amounts to some 25 per cent. — The large increase in the radiant energy directed upon the film has made it necessary to employ a heat filter in the condenser system. — Refinements in the present system are expected to produce additional small increases in illumination, and it is believed to be possible to develop other special equipment to take adequate care of the few (special) cases where it is necessary to project upon an unusually large screen.

Print ISSN

0097-5834

Published

1937-02

Content type

Original Research

DOI

10.5594/J08571