 Pauline Squibb |
development time for pulled film Hi, I know that if you push your film by one stop you need to over develop it by 33% of normal development time for every stop that you pushed. But how much do you reduce development time by for film that has been pulled?
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Jon Close |
Depends on the film and chemical developer used. C-41 (color print, chromogenic b&w) is fairly standardized at 3:15 @ 38°C (100.4°F) for normal developing and +0:30/stop push, regardless of ISO or manufacturer. Pull developing is not recommended. Actually, push/pull processing is generally unneccessary with C-41 film due to its wide exposure latitude. E-6 (Ektachrome/Fujichrome/Agfachrome etc. color slides) is similar, but push/pull is done with +/- 2:00/stop. Traditional B&W development times depend on both the specific film being developed and the chemicals used. Best to refer to the manufacturer's specific recommendations.
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Jon Close |
More, re "pulling" C-41 film. Pull generally refers to giving the film greater exposure, eg. expose ISO 100 film at ISO 50. With tradional b&w and slide films this would require pull processing (less time in the developer) to compensate. C-41 film is such that most react very favorable to +1 or +2 stops "over" exposure with normal developing.
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Pauline Squibb |
Thanks for information so far. I was curious about black and white only. It is true that whatever the film or the developer used you add 33% for each stop that you push the film. i.e. if you push a Kodak 200 ISO to 400 ISO and lets say the dev time for 200 ISO in Ilford ID11 is 6 minutes then you add 33% to account for the pushing making your dev time 8 minutes. Isnt there a similar equation for pulling in black and white no matter what film or developer?
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Jon Close |
>>"It is true that whatever the film or the developer used you add 33% for each stop that you push the film. i.e. if you push a Kodak 200 ISO to 400 ISO and lets say the dev time for 200 ISO in Ilford ID11 is 6 minutes then you add 33% to account for the pushing making your dev time 8 minutes."<< I don't believe that is exactly true though it might get you in the ballpark. For example, the tech sheet for Ilford ID-11 lists varying times for various films. For Delta 100 the normal time is 8:30. A 1 stop pull to ISO 50 subtracts 1:30 (17.6% reduction in time). For 1 stop push to 200 add 2:00 (+23.5%). For TMAX 400 the ISO 400 time is 7:00, 1 stop push is +2:30 (+35.7%), 2 stop push is +5:00 (+71.4%). A 1 stop push for Fuji Neopan 400 is just +1:15 (+16.7%), while 2 stop push is +6:00 (+80%).
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Pauline Squibb |
Ok, so it gets pretty complicated, and the answer is to be found in the appropriate tech sheet for film and dev combined. Thanks for info.
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