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Old 10th August 2020, 03:04 PM
Terry S Terry S is offline
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Default Can a developer be tested on a film leader?

I'm sure that I've read somewhere before, that one can put a few drops of FULL STRENGTH developer on a film leader to test it's ability to develop a whole film.

Having done this yesterday, I got one developer to work and one not (this is mentioned in passing in another thread I have just started).

So have I remembered this correctly, but more importantly can one rely on this test with full strength developer, or is it necessary to develop a film leader in the correct diluted strength for the full time for each film?

I am asking this question because of two instances. Firstly I had a bottle of Rodinal die on me not that long ago, even though I had only used it to develop one film, so it was very new. And then yesterday (09/08/2020) a fresh batch of home mixed D76 / ID11 did the same, in that the first film developed fine at 1 :1, and then the second one came out EXTREMELY thin with fresh 1 + 1.

So can I rely on this slightly quicker test to confirm a developer is working okay, or have I just remembered a misquote?

Terry S
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Old 10th August 2020, 04:35 PM
Mike O'Pray Mike O'Pray is offline
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Terry I can think of no reason why this should not work in that it will indicate if the developer is still working but I am not sure it will tell you enough to conclude that the developer is completely OK

What I do takes longer but does help me decide if Xtol in my case is still 100%

I place the leader in a small dish with my usual dilution and then develop it with some agitation for the correct time for what ever the film is. I then give it a quick swish in fixer and a very quick rinse.

I then hold it up to a clear incandescent tungsten bulb filament(100W) and the filament should be dim enough to appear as a solid orange line. If it is then I will trust the developer.

What is missing from this test is that ideally you ought to have kept a leader developed fixed and washed reasonably well so it won't deteriorate and use this as the template. If the test leaded matches the "standard" leader in the filament test then you know you are good to go

The problem with no yardstick to judge against is deciding whether the black leader is black enough. For instance when my Xtol was on its way out it still seemed to past the test but when held up against the yardstick leader the tungsten filament was clearly brighter

I hope this helps

Mike
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Old 10th August 2020, 07:15 PM
Svend Svend is offline
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^^^ What he said

I test almost all my developers now by doing the leader dunk before throwing a film into them. Just as Mike does, I immerse the leader in a little dish of stock or working strength developer (depending on the brew) and leave it there for five to ten minutes, as appropriate. If it doesn't turn black I don't use the stuff. This has become so routine I don't even think about it now. Takes no time at all -- it sits in there while I fuss around prepping all the other bits and pieces for the developing session. I do this with fixers too.
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Svend
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Old 12th August 2020, 12:30 PM
Terry S Terry S is offline
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Thanks Mike and Svend for your comments. They definitely make sense and I think I will follow them each time I go to develop a film from now on.

Terry S
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