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Push-processing in a documentary from 30s

Silvie Hauser

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Hello everyone, I've got some questions about materials and push-processing in the 30s. I'm working on a the British documentary "Coal Face" (1935) by GPO film unit. There is quite a bit of information on GPO in general but almost nothing on that particular film. I studied photography, so I could tell just looking at the film that some parts of it were heavily pushed. Since it's a scientific paper I can't just "know" it's the case, I have to bring arguments in favour of it. And while I know that the extreme graininess and high contrast are good indicators for push-processing, it would be even better if I could find further proof, and that's where my questions start.


I'll include two screenshots from the film, that demonstrate the huge difference in quality. The first screenshot is from a scene above ground inside a building whereas the second was made in a coal mine.

post-76405-0-80469000-1551220578_thumb.png post-76405-0-05556500-1551220587_thumb.png


According to one of my sources [Enticknap, Leo. "Technology and the GPO Film Unit" The Projection of Britain: A History of the GPO Film Unit. Eds. Scott Anthony and James G. Mansell. London: Palgrave Macmillan on behalf of British Film Institute, 2011. 188-198.], the camera used by GPO was a Autokine with a 50mm/2in lens with a minimum aperture of f1.9, most likely one of these: https://www.scienceandsociety.co.uk/results.asp?image=10405810

Does anyone know where I could find out which stock they used? At the time most likely panchromatic, but that's about as far as I got.


The other thing is, I found lots of information for photography and push-processing but next to nothing on film and push-processing, though I'm assuming it must have been quite common, especially in the documentary movement. If anyone knows of any (quotable) source for this kind of information, it would be a great help. I found some websites but a published book or an article in a journal is always preferable.


Thanks a lot!

Edited by Silvie Hauser
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That's a very specific question, and from a long time ago. I'd be very surprised if you found a better source than the book you already have.


You have a video tape or file of this material, apparently. That would have been made from a film element at some point, probably reasonably recently (in the last few decades, as opposed to 85 years go when it was shot.) Do you know where your video material came from? Can we find out, and perhaps find the original film element which might have some more clues?


I'm near London, if it's here, and if I can help, I happily will. This sort of detective work is fun!



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I couldn't conclude from the second screen grab that the film had been pushed; I would put the high contrast down to the lighting- a hard source with no fill.

As Phil implies, you can't deduce much from an indifferent telecine. Modern scanning is a different matter, but I don't think that's what you have.

There are some 30s and 40s-era "American Cinematographer" magazines on archive.org which might have some references.

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I know it is a bit tricky. Still, some more digging produced some more precise results! I found this extended version of the article I quoted above on Enticknap's personal website: http://enticknap.net/leo/index.php/research/chapters/gpo/

In there he goes into more detail as to what technology was used. The information I gained was that the fastest film stock available at the time (before 1938) had EI40. And he also mentions Gasparcolor but since Gaspar was specialised in colour film the stock for Coal Face was probably a different brand.


One option I'll try is certainly to leave a comment on Enticknap's website and ask whether he knows more. Clearly he did a lot of research on their technology and might just know it.


The information I got on the dvd version is as follows: it is part of a relatively new (10 years old) dvd package released by BFI in 2008, named "Addressing the Nation: The GPO Film Unit Collection, Volume 1"

In the booklet it has extra information on the films and the transfer process, I'll quote the relevant parts:


All of the films included on this GPO Film Unit compilation are preserved by the BFI National Archive.

The programming of this DVD is the result of an on going assessment of the GPO Film Unit's output held within the BFI National Archive. A partnership with Royal Mail, The British Postal Museum & Archive and BT Heritage has allowed the BFI to examine closely the current condition of elements held within the archive and where necessary has enabled new film elements to be produced.

This work, carried out by our archive consultant, Steve Foxon, has enabled us to access the best possible existing source materials for this DVD collection and thus new digitally graded transfers have been produced for all the films in this programme.

Given the age of these films, it is inevitable that the new transfers will show some defects in the source materials. Picture elements occasionally exhibit damage in the form of dirt, scratches, and missing and/or unstable frames. There are also instances where noticeable variances in quality occur between stock library materials and newly shot footage. [...]

So I guess this mentioned Steve Foxon is another person I could try to find and contact. Thanks a lot for the idea of trying the DVD as a source, extra helpful that it even gives a name to try. I'll see how far I get there and will report back. I think at the moment this is something I can do myself to just try and contact them but if it requires someone going there personally I'd be very grateful for your help indeed.

If I manage to get more exact data on the film stock I might even be able to estimate by how many stops they pushed the material.

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40 ISO isn't too bad- remember the shutter speed is only about 1/60 and artificial light was used- but it's quite possible it was pushed. You might need to see the negative to identify the stock.

There are a few references here


to suggest that Selo (50ISO) was availabe in 16mm. but of course the GPO would be using 35. Faster stocks aren't around until later as you say.

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