The other day I spoke to the biggest source of knowledge himself, Mr. Paul Weston. We were chatting away about all things darkrooms and photography, when he told me a fascinating tip I can’t wait to try out: develop a film to become incredibly sensitive to light.
Films like Delta 3200 or HP5 allow you to shoot at whichever speed you see fit (within a range of 400 to 3200 ISO that is), by compensating developing times. It’s not recommended with every film of course, but maybe we should disregard this statement on the manufacturer’s packet.
Paul used to shoot sports for newspapers back in the days, when the most sensitive film was the Ilford FP4 at 100 ISO – a very fine grain black and white negative film. I remember that when I started shooting 25 years ago, the HP5 was already well established. I’ve never even considered life without it.
You can imagine that 100 ISO on a cloudy day isn’t exactly the sports photographer’s choice when it comes to capturing fast movement, when all you have is your camera telling you “use your widest aperture with about 1/4th of a second”. Forget it!
So Paul and his colleagues shot at much faster shutter speeds to capture the motion properly, disregarding the film’s speed. When they came back to develop their film, they’ve used a technique to exploit the reciprocity failure of the film.
Here’s how they did it:
Using regular one-shot developer, Paul would agitate the film for as long as it says on the packet, as if it were a 100 ISO film. Once that’s over (say after 4 minutes), he’d stop agitating the tank, pop in on a shelf and go to the pub for several hours.
Upon his return, the developer would have completely exhausted itself – gradually darkening the film like we know from traditional push processing (with added ker-pow factor). Ending the process with stop and fixing baths, the film would come out a very grainy – but at least yielding pictures usable for newspapers.
“The important thing is not to agitate the tank while you’re overdeveloping, otherwise you end up with a completely black roll of film”, says Paul. Thank you for the tip!
I can’t wait to try this out, but am not sure if I should use FP4 or HP5 (the latter might be too sensitive and could easily come out black after half an hour). I’ll try this out with an old bottle of Ilford HC10 concentrate, made up as 1+31 – a close enough dilution to one-shot developer.
I’ll keep you posted – when I’ve got results, they’ll be here on the site.