Brian R Pritchard Motion Picture and Film Archive Consultant

 

 

 

 

 

 

 

Film Width - Metric or Imperial

It has always intrigued me as to why film was sold in metric width and Imperial length.  I decided to carry out some research. 

This is an extract from an article by Carl Louis Gregory in the J. S. M. P. E. Volume 14 Jan 1930  titled 'The Early History of Wide Films'

That the 35 mm. width of film came to be the measurement which survived and eventually became standardized is, so far as the writer has been able to ascertain, a coincidence.  It was not foresight that caused Mr. Edison in this country and Lumiere Freres in France to select film widths that were so nearly the same that they were practically interchangeable. It was pure chance, also, that these two firms happened to be the most powerful commercially in their respective countries.

Edison selected 1 3/8 inches as the width of film best suited for his Kinetoscope only after a long series of experiments with films in cylinders, disks, and narrow ribbon form run horizontally instead of vertically.  This measurement coincides within 1/100 of an inch with the 35 mm. width selected by Lumiere and, while Lumiere used only one round perforation on each side of the film and Edison used four rectangular ones, it was possible, by altering sprockets or by reperforating the Lumiere film, to use them interchangeably.   Lumiere later reluctantly abandoned the two-hole perforation and copied the Edison standard in order to sell film to users of Edison machines.

This is an extract from an article by Loyd A Jones in the J. S .M. P. E Volume 21 1933 titled  'Standardization in the S. M. P. E'

One other point which had been under discussion for some time was the maximum cutting width for 35-mm. film.  At this meeting (October, 1924) the Society gave its initial approval to 1.378 inches instead of the 1.375 inches, thus making this width correspond as precisely as possible to 35-mm. rather than to 1 3/8 inches.

 

 It appears that Eastman's film in the UK in 1912 was supplied as 1 3/8 inch width and  lengths in feet.

1 3/8 inch is equal to 34.9 mm.

1 3/8 inch = 1.375 inches

35mm = 1.378 inches

The Kinemacolor Company  on February 5th 1912 signed a contract with Kodak Ltd  “to supply cellulose nitrate “cine” film to the customer for the purpose aforesaid, of a width approximately thirty-five (35) millimetres, or one and three-eighths of an inch (1⅜) unperforated f.o.b. London at a price of one and forty-five one-hundredths (1.45) pence per running foot[1], all such film to be in standard “cine” lengths of two hundred (200) feet and four hundred (400) feet.”

 [1] £0.006 per ft - $0.0030 per ft

These measurements also seem to have applied in Europe. An Agfa can label is shown below. The width is given as 34.9mm - 1 3/8 inch the length is shown as 60 metres.

 

 

 

In the SMPE standards of 1928 the width of the film is shown as 1.37795"( 35mm) to a minimum of 1.37598" (34.95mm) width even at this point the primary measurement is Imperial but is no longer 1 3/8 inch exactly.

The Dupont label below gives the width as 35mm - 1 3/8 inch;  Length 1000ft - 304.8metres. The Primary width is metric and the primary length Imperial.

The Imperial width was continued for some years on Kodak stock. The label below it is just discernable as "Kodak Release Positive 1301, Neg Perforations, For Technicolor".  Kodak Fine Grain Release Positive 1302 was introduced in 1938 so it is probably before that date.  It gives the two widths and lengths but with the imperial measurement first.

All this does not answer the question why do we still use imperial length - well it is because we get an exact number of frames to the foot; 16 frames per foot on 35mm and 40 frames per foot on 16mm. Obviously once the metric width had been established as the primary measurement by the USA it was then standard throughout the world, but the imperial length retained out of convenience.