Developer Activity Test

Discussion in 'B&W: Film, Paper, Chemistry' started by philldresser, Nov 4, 2005.

  1. philldresser

    philldresser Subscriber

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    I have gotten into the habit of saving all my film leaders (35mm) cut off before loading films onto the development reels and use them to test the activity of the developer.

    I simply take 20-30ml of mixed dev in a saucer and place the film leader in and leave for a few mins while I load the reels. If it goes black then at least I know the dev is working.

    This came about after getting a clear film when my Pyrocat-HD had past its prime. Now I hopefully wont run into clear negs again (for that reason anyway)

    Is this a valid test? Anyone do something similar?

    Phill
     
  2. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member

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    I started doing that with my deep tank of Acufine when I haven't used it for a while after having a "clear film incident" (probably the result of the developer overheating while we were on vacation during the summer and our building's air conditioning went down for a few days). I just cut a strip from a sheet of 4x5" that I have set aside for the purpose to make sure it goes black in about a minute or so. Actually I put about half the strip in the developer, and then put the whole strip in the fixer to make sure that's okay too.
     
  3. df cardwell

    df cardwell Subscriber

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    You bet. Doesn't everybody ?

    Save those leaders: you can do a fine control test as well, measuring your DMAX.
     
  4. BradS

    BradS Subscriber

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    Hey, I always thought the leader (and the 25th sheet in a box of 4x5) was for testing the fixer. Now, I'm all confused.

    Good idea. Thanks.
     
  5. titrisol

    titrisol Member

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    It can be used for both, clip it in 2!
    Undeeloped film has to go clear on fixer

    Donald Qualls taught me to use the leader for developing time estimates:
    - Make the leader wet, dump it in the developer with agitation
    - Take the time until it becomes dark grey (not fully black) and multiply that by 5 as starting point.
     
  6. srs5694

    srs5694 Member

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    The described clip test is frequently recommended for users of XTOL, since that developer has a reputation for going bad suddenly and without any obvious visual indicators (until you see the blank negatives, of course).
     
  7. Tom Hoskinson

    Tom Hoskinson Member

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    Yes, I use small pieces of fim to test both developer and fixer.
     
  8. gainer

    gainer Subscriber

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    There is one thing to look out for if you are using the leader test to estimate developing time. If the snippet has had a long exposure to light, it will not darken as rapidly as one that has been kept in the dark until just before the test. I attribute this effect to the film having been exposed to near or beyond its reversal exposure. Better to keep the film you test for developing time in the dark.

    If you pull a little piece of film out of a cartridge and develop it with the piece that was already out, you can see the difference.
     
  9. gainer

    gainer Subscriber

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    I wasn't clear enough. I meant for the developing to be done in room light. You would think that film that has had a long exposure to room light would develop more rapidly than film that had been kept dark. 'T aint necessarilly so.
     
  10. df cardwell

    df cardwell Subscriber

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    Right on, Gadget !