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17.5mm FILM SIZES!

When cinematography first arrived in the 1890's, the flexible film stock seems to have been supplied as unperforated 35mm. Hence the first attempts used 35mm, according to Brian Coe in his "History of Movie Photography" the first amateur equipment may have been the Amateur Kinematograph produced by the German manufacturer Oskar Messter in 1897 using standard 35mm film, the camera could also be used as a projector.

Very soon the 35mm film was being split into two and perforated in various ways. Birt Acres demonstrated a 17.5mm camera, patented on 9 June 1898, to Croydon Cine Club on 25 January 1899, and the "Birtac" was put on the market in the UK in May 1899 at 10 guineas. The hand turned wooden camera used 50 foot (15.2 metres) of the standard 35mm film split down the middle. The camera could be used as a projector by attaching a lamphouse and reversing the lens.

On the 24 March 1899 another 17.5mm camera appeared in the UK, demonstrated by T.C. Hepworth at the London Camera Club it was advertised at 11 guineas as a combined camera, printer and projector. The "Biokam" used 17.5mm film with central perforations - it could also be used for still pictures.

Other 17.5mm systems included "La Petite Cinematographe", 1900. using centrally perforated 17.5mm film and the first German Ernemann "Kino" cine camera (1903) which again used centrally perforated 17.5mm filmstock to produce a picture of 16mm x 10mm. The "Duoscope" apparatus, introduced in 1912, used a 17.5mm film with two perforations on the line between the frames. A built-in electric lamp enabled the device to also act as a projector.



During 1917, in the USA, another 17.5mm product was launched by Movette Inc. of Rochester, New York. The "Movette" used magazine loaded 17.5mm film with two circular perforations on each side of the frame. Although the negative film used in the camera was still the highly inflammable nitrate stock, positive projection prints were made on the Eastman safety stock.

Perhaps it should also be mentioned that ready perforated 35mm film stock was often used split to 17.5mm, for recording optical sound tracks ready for editing etc. in the professional film industry. This 'half 35mm' stock will run normally through most 35mm editing equipment. In the early 1930's when the Baird Company was struggling to improve the scanning disc television system, they eventually used an 'intermediate film system' for televising studio scenes - this consisted of a normal film camera, fixed to a continuous processing tank - the scene was filmed, picture and sound, processed and then scanned (still wet) using the film scanning system they had perfected. To save on costs the Baird Company used split 35mm filmstock - ie 17.5mm for this process.


In 1926 the Pathé company launched a new 17.5mm size, presumably as a competitor to 16mm, as their smaller 9.5mm gauge had already begun to sell rather well. The new Pathé 17.5mm gauge, launched as the "Rural" in France, used safety stock with a picture size of 9mm x 12mm, and was shown at the Société Français de Photographie on 10 February 1926. Printed films were produced by printing in pairs on specially perforated 35mm safety stock by reduction from 35mm originals. It seems in France the size was intended for use in the smaller country district (hence 'Rural') cinemas on the Pathé circuit. Marketing in France began in earnest in 1927, 15th November to be precise, with Jacques Pathé - Charles' nephew, as Director of Pathé Rural, with publicity entrusted to M. Marette (the engineer who had developed the system); M. Marin, Marette's son-in-law and Theophile Pathé. However problems with equipment and film production, together with obtaining film distribution rights slowed business. In the UK the silent 17.5mm system was hardly advertised at all by the UK company Pathéscope.

The French made Pathé 17.5mm silent projector was marketed as the "Rural" in France; the "Rex" in the UK. Around 1930 a cinecamera (sold as Pathé 17.5mm motocamera in France; the "Rex" in the UK) was also introduced. This looked like an overgrown 9.5mm Motocamera and used a similar design film charger. The Pathé 17.5mm film size had arrived!

"Rural" & "Rex"


It is important to note that the commercial Pathé 17.5mm film system was NOT "standard 35mm film slit in half" as some other web-sites and even technical books quote authoritively. Although the 17.5mm picture frame height (9.5mm) is about half that of the 35mm cinema size picture frame height (18mm) , Pathé 17.5mm has one sprocket hole per frame whilst standard 35mm has 4 sprocket holes per picture frame. The size and positioning of the sprocket holes is also different between Pathe 17.5mm and standard 35mm. Yes the 17.5mm printed films used 35mm wide filmstock to print two copies at a time, but this was specially perforated 35mm filmstock - not standard 35mm cinema stock.

This confusion arises partly from the fact that the commercial cinema has used 'half 35mm' - ie 35mm filmstock cut in half, for sound track work - as the sound track occupies such a small portion of the 35mm filmstock it is considerably cheaper to use 'half 35mm' for this purpose. In later years when magnetic souind recoprding was adopted, this was also supplied as 'full-coat' just 17.5mm width, but with standard 35mm perforations. So in trade catalogues 17.5mm filmstock was listed, but this is not the Pathé format!! Incidentally in the early days of television, the Baird company also used 35mm filmstock slit in half - this was for the 'intermediate film system' where a cine camera recorded the scene, the film was rapidly processed and then scanned for transmission (don't ask! - there are many books and no doubt internet pages about this - my site is for vintage film!!)

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Updated 14Oct2014 - Last paragraph - "Pathe 17.5mm not half 35mm added / 03Oct2016 - some rewriting to clarify things!
Created 21July2001 ........ Last updated: 03 October 2016 .............. 175hist.htm ............. @Grahame L. Newnham