Optics of Projectors for 16 mm. Film

The limits of illumination available in a projector are fixed by three factors: the size and brilliance of the light source, the effective aperture of the optical system and the design of the condensing lenses. In modern 16 mm. machines of the standard type, about 100 to 120 lumens are available through an f/2 optical system; these values, which are not corrected for shutter and film losses, mean that 1.6 to 2.0 per cent of the total radiation is being used. The use of low voltage lamps has not changed this ratio to any extent. The effect of varying each of the above factors is discussed, and the increase in screen brightness that is likely to be obtained is estimated.

Print ISSN

0097-5834

Published

1932-04

Content type

Original Research

DOI

10.5594/J01338