Film Dimensions

I must start with an apology. Many of the images in here, I came to realise as I went thru them, were accumulated in days long before I had any thought of a website. At that time I was just copying stuff of interest to me, and seem to have failed to always record and show where information came from. If anyone has an issue, please contact me and I will add a credit or remove the offending item.

I have been reviewing this page to renew the pictures and trying to introduce a bit more logic than there was in the past. It's tricky to know how to break the subject into manageable chunks without missing bits. However, let me start with a brief historical survey. It all started of course with 35mm and even the Americans were forced to use 'mm' instead of 'in' sometimes. Not only did 35mm rapidly become established as the de facto standard but a vitally important part of the process was SMPE (as it then was) standards for a variety of technical aspects and dimensions. The final leg of this tripod was the establishment by Bell and Howell of machines of a very high standard of accuracy for perforating and other processes. Although many other formats were tried, 35mm remained the near-universal standard for cinema until film was replaced by digital. The so-called "sub-standard" or, as I prefer, narrow-gauge formats were all influenced, if only obliquely, by the 35mm standard.

The most directly-derived format was of course 17.5mm. There were various attempts at a 17.5 format but only one, the Pathé Rural, was ever used commercially on any scale (I except the 17.5 size, more properly regarded as half 35 than a format in its own right,  that was used in some back-room processes in the industry). The other most directly-derived format was of course 9.5mm, again from Pathé. Something I regard as important about both 17.5 and 9.5 is the fact that they both lacked the degree of consistency, quality and repeatability conferred by the standards I have mentioned above that ruled 35mm, not least because they were principally Pathé gauges and relatively little adopted by other major concerns. Even Pathé's own 28mm had been standardised through American efforts, annd 16mm too had an SMPE standard, which in turn largely passed through to Standard 8mm. Super 8 was in a way sui generis as it was, uniquely, a deliberate development beyond an existing narrow-gauge format (Standard 8 I exclude because it just used the old sprocket holes of 16mm, ludicrous though this was in terms of picture size). However, Super 8 was, I believe, deliberately designed for general adoption and was correpondingly highly standardised, even if not by the SMPTE. I have, incidentally, never really swallowed the story that 16mm derived just from an objective consideration of all the technical factors. I am sure Kodak was aware of what Pathé was up to but didn't like centre sprockets. Bell and Howell had done the more logical thing and developed a 17.5mm prototype, but were trumped by Kodak's oven-ready 16mm. A pity; Kodak's choice and the marketing muscle behind it made 16mm the de facto standard for semi-professional use, despite 17.5mm being so much more logical. VHS and Betamax re-played.

I'm not going to make any more general comments as I'm sure many will disagree with some of the foregoing. In conformity with the main gauge-based structure of the site, I shall see if it works dividing things up by gauges, starting with my first love, 9.5mm.

Because of the rather proprietary nature of 9.5 there is little formally-published information. I have, however, come into possession of some Pathé technical drawings about Duplex (thanks mostly to Ken Valentine) and have spent some time processing them into a presentable form. But first, Pathescope's description of the 9.5 process as published in Pathescope Monthly.

I have taken the unusual step of reproducing these pix in full size rather than as the usual expanding miniatures because they are so basic to 9.5. The third is just an enlargement of part of the second. This stuff I shall leave largely to explain itself, but I would just add that these images help show where problems of lack of standards and quality control familiar to 9.5ers can arise. First, note that the printing and development is all done before perforation. This is sensible to minimise the interfeence of sprocket holes with circulation of development chemicals, but it can and often does result in differences in precisely where the sprocket hole appears in relation to the picture. Hence the need for some form of framing device or racking, although this was far from normal on Pathé projectors. The second issue is similar in principle but applicable only to notched films. As can just be perceived in the enlargement, the edges of two of the prints are very slightly notched in a squared cut-out opposite the main notch. The displacement of the notch even slightly can produce this second notch, familiar as a sharp uneven edge to many a 9.5er. I am indebted to Patrick Moules for this explanation of something that had long puzzled me. I shall look for the third print in future.

I shall also produce this next image  (from P. Moules) in a large format; it shows how complex the whole process could get, with all manner of different dimensions arising from a variety of factors. I spent a lot of time on this one, which has appeared in 9.5 magazine.

This, incidentally, is what I started with.

In the sound era, too, Pathé/Pathescope failed to control quality to high enough standards. I don't recall Pathescope doing anything quite as crass as printing the sound track in negative, as Pathé France did at first, but there was a fair bit of picture weave in films like Glass Mountain. It was obviously expected from the start that sound tracks would wander, as witness the sound reader on the Vox and I have encountered the same phenomenon on 17.5. Limited as the availability of documents in the UK and in English is, I can offer only two images of sound film "standards" for 9.5.

Pathescope with typical modesty described 9.5 sound as "the greatest achievement in the history of cinematography". If only they had rigorously pursued these standards. (Both images are I think from Pathescope Monthly.) Some films were issued with re-recorded sound, but by no means all, as witness Edge of the World for example.

Then there was Duplex, about which I shall not comment, beyond saying that it seems to be commonly viewed as one of the last nails in Pathescope's coffin.

The last image is from a Pathescope catlog.

Now another thing about 9.5 sound. Here is a note I put together from responses by Graham Newnham to a magnetic sound query I raised with him, in about 2006. Just a small sample of the sort of knowledge we lose with people like Grahame.

9.5 mag std