A Method for Converting 16mm Silent-Speed Footage to Normal Sound-Speed of 24 Frames/s

Most early medical motion-picture footage was photographed at a camera speed of 16 frames/s. Today, most of this film is irreplaceable from an historical aspect or because of the rarity of the subject matter. However, if such archival material is integrated directly into modern productions designed to be projected at sound-speed, the rate of motion in the old scenes is seriously distorted — often with an undesirable comic effect. Conversion is obtained by projecting 16-frames/s footage onto a translucent screen at 18 frames/s. This is rephotographed with a 16mm motion-picture camera with a sync motor at a normal rate of 24 frames/s. To eliminate flicker the projection equipment used must have a flicker rate above that which can be perceived by the eye and the camera. The flicker rate on the equipment used in the conversion technique is approximately 54 flickers/s. A series of tests easily determines the proper shutter openings on the camera itself.

Print ISSN

0361-4573

Published

1967-11

Content type

Original Research

DOI

10.5594/J13667