A Review of Projector and Screen Characteristics and Their Effects upon Screen Brightness

Two fundamental factors determine the light output of the motion picture projector: (1) source brightness and (2) the effective aperture of the projection optical system. When these are known accurately, the number of lumens available for screen illumination can be computed, after making allowances for losses that occur in the collective element, the shutter, and the objective lens. The method of computation is described, and results are given for typical projectors. It should be noted, however, that adjustments are made in the practical operation of projectors that can produce wide variations in the two fundamental factors. Therefore, the conditions of operation must be precisely known in order to apply the results to any particular installation. — Screen brightness can be derived directly from the lumen output when the screen factors—area, reflectivity, and directional properties—are considered.

Print ISSN

0097-5834

Published

1936-05

Content type

Original Research

DOI

10.5594/J08678