Modified Negative Perforation: Proposed as a Single Standard for 35-mm Negative and Positive Motion Picture Film

W. G. Hill

The existence of two or more perforation shapes for 35-mm films has, for many years, been considered undesirable. For processes requiring accurate film positioning, the dual Standard of Negative perforation for camera stock and Positive perforation for release stock does not suffice. Registration problems are minimized if Negative perforations are used throughout; experience, however, has shown that projection life is short. The Modified Negative perforation, with fillets at the corners, has improved resistance to tear while preserving the general negative form corresponding to conventional piloting means. Tests conducted show that better film positioning is accomplished in conventional camera and printing equipment for film with Modified Negative perforations than for film with Dubray-Howell perforations. The method of evaluating film location during exposure and printing is described and evidence of results presented. Photoelectrically recorded charts show the extent of out-of-register which resulted for various combinations of perforation types. Film-life projection tests indicate that the Modified Negative perforation is equal or superior to the Dubray-Howell perforation.

Print ISSN
Published
1951-08
Content type
Original Research
DOI
10.5594/J05054