Factors Contributing to Unsteadiness in 16mm Films by L J Wheeler - November 1968
This is an extremely interesting article, technically, especially with its description of film perforating.techniques.
Summary
FACTORS CONTRIBUTING TO UNSTEADINESS IN 16MM FILMS
When reduction prints from 35mm negatives are made onto 16mm film, screen picture unsteadiness may be caused at any of the following points:
(1) in the 35mm negative,
(2) in the 35mm intermittent mechanism of the printer,
(3) in the 16mm intermittent mechanism of the printer,
(4) in the l6mm film perforations and
(5) in the 16mm projector mechanism.
The accuracy to which these various mechanisms and films must be made is discussed. An outline of the basic principles of film perforating is given and the standards relating to perforating tolerances are considered. An important tolerance which has so far been omitted from the specifications for 16mm sound film is described. A practical specification to cover this point is suggested. The importance of standardisation in 16mm projector intermittent mechanisms is discussed and the effect of various mechanisms on the resultant screen picture is shown.
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