The Effect of Aperture Lenses on Illumination

The complexity of the geometrical optics involved in a motion picture projector leads to numerous proposals for improving illumination in some respect that look plausible at first glance but generally fail in practice. Among such proposals we might consider the addition of a small collective lens in the immediate neighborhood of the film gate. Careful study of the transmission of light from source to screen reveals the fact that in some reflector arcs such a lens can improve evenness of illumination and in some cases raise the general level, although the latter could have been taken care of in the design of the lamp. In a typical condenser equipment with the 13.6-mm. high-intensity arc no possibility of improvement was found either in an analytical study or in experimental tests.

Print ISSN

0097-5834

Published

1934-12

Content type

Original Research

DOI

10.5594/J08749