Pushing a 400 ISO film to 1000 ISO?

Question

I pushed a Kentmere 400 ISO to ISO 1000 and can't find any development chart that shows what time to develop it for. The developer i'm using is Ilford ID 11 1+1 . I estimated, from the dev times of 800 and 1600 to develop of 21 minuets, anyone have any insights? thanks

Answer 1

Hi Fred, I routinely push Kodak Tri-X 400 to 1600 as well as other films.



You have backed yourself into a corner with a couple problems:



1--I wouldn't recommend shooting something that you intend to process yourself without knowing how to do so. Look up the information first, then shoot a test roll, see if your information was correct and then proceed. You risk ruining these shots now.



2--Why did you rate your film at a non-standard speed? Print film has a lot of latitude so it's totally unnecessary to dial the ISO in between full stops. That is a job better left to your camera settings.



3--You should choose a developer suited to the film you want to use and it seems like ID11 at 1+1 is going to take an unusually long amount of time to process to Kentemere 400 at 1000 ISO.



Kentmere 400 has not yet been added to the Massive Development Chart which tells me that not many people are using it as this is really the definitive source of processing information. In my viewpoint, anything done that is not on this chart, is somewhat experimental.



The PDF of information on this film, however is available at DigitalTruth.com (and probably Kentmere's site)



http://www.digitaltruth.com/products/kentmere_tech/kentmere400.pdf



For 800 ISO, they suggest 20.5 minutes at 68 degrees in the 1+1 solution.



You're probably not going to find any documentation of anyone shooting at 1000 ISO exactly so all you can do is estimate. Shooting it above 800 is not even recommended by the manufacturer apparently.



I process Tri-X in HC110b for 1600 ISO and it takes about 16 minutes. Delta 3200 to 1600 in HC110 takes around 14 if I recall. To me, processing much longer than that and you may as well be stand developing.



But maybe there are specific reasons why you are verging off path. And in any case, I certainly wish you luck and am sorry that I cannot offer a concrete answer! Maybe now's a good time to shoot a test roll and try your guesses out on it, doing a snip test as jeannie has suggested.



METAL AND MANUAL

FILM FOREVER

Answer 2

You can do a snip test - load about 6 inches of hte film onto the reel, put the rest back in a light tight container. Develop the film at 21 minutes and see what you get.



A rule of thumb that always worked for me is add 10% for the first stop, 5% for the second. 1000 is 1.5 stops faster than 400, so take the 400 time and multiply it by 15%. Add that to the 400 time and develop for the total amount of time. You could snip test this instead of the guess.

Answer 3

Push processing involves prolonged development to build density in an under exposed film. Find the normal developing time in seconds. Multiply by 1.25 to calculate revised developing time to push process 1 f/stop. Multiply by 1.5 to gain 2 f/stops. 3 f/stops is twice normal. These are just rules-of-thumb, best to find manufactures specifications or to test for yourself.

Answer 4

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