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  1. #21
    Ian Grant's Avatar
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    The type of developer is significant too, a PQ developer (or Dimezone) is a significantly better than an a comparative MQ developer, the fall off is slower, and greater throughput.

    Bromophen is of course Bromide paper Phenidone/Hydroquinone based

    Ian

  2. #22
    Bob F.'s Avatar
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    I tend to use factorial development (usually 5-6 times initial appearance of the shadows) - I suspect the story is more complex as bromides and other chemicals build up in the brew as more and more paper is developed, but it seems a good approach in practice.

    A simple test for fixer exhaustion, which others have pointed out is more critical, is to do a film clearing time test. Again, I'm sure it has its technical faults but the method seems to work well in practice.

    Drop a piece of undeveloped film leader in some fixer and swirl it around gently (I actually sacrifice a roll of FP4+ for this job - you only need a small piece each time so it lasts months). Time how long it takes the piece of film to go clear (it will probably still have a slight purple tint - ignore that). This is your base time. Every ten 8x10" or equivalent prints do the test again. If the time for the piece of film to clear doubles, dump the fixer. To be safe, I dump after around 50% longer than the base time by which time I find the silver content of the fixer has started to approach the 1g/l level (you can buy test-strips to measure silver content but they are a bit coarse, indication starting at 1g/l) and as Ilford recommend 0.5g/l for "archival" fixing and 2g/l for "commercial" use, I figure that's sufficient. I guess this early dumping also prevents other by-products from building up too, but it needs someone more knowledgeable than I to say what they may be - the important point is that they (hopefully) do get the chance...

    If in doubt, follow the manufacturer's recommendations: you will probably spend a little more on the chemicals than is strictly necessary but you will not go far wrong. I'm a control-freak so I measure and test as best I can (not being a chemist) but if that is not your style, there is nothing wrong in just following the instructions!

  3. #23
    BetterSense's Avatar
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    Time how long it takes the piece of film to go clear (it will probably still have a slight purple tint - ignore that). This is your base time. Every ten 8x10" or equivalent prints do the test again. If the time for the piece of film to clear doubles, dump the fixer
    Why test with film, when you are fixing paper?

    I only use RC paper. I just drop a fresh test strip in the fixer and wait 10-30 seconds. I then rinse the strip off and throw it in the developer. Next time I turn the lights on, I find out if my fixer is still working, because the test strip will either stay white or go grey. If a test strip clears and stays white with 15s, in the fixer, I know I'd doing fine as long as I fix a minute or more. In reality prints often sit in the fixer for several minutes until I get around to moving them.
    f/22 and be there.

  4. #24
    Ian Grant's Avatar
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    How did you manage to quote a fixer test in a developer thread ?

    Time to change yiour name to NonSense

    Ian

  5. #25
    Bob F.'s Avatar
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    My fault Ian - I went slightly OT...

  6. #26
    Ian Grant's Avatar
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    Bob, my aunt reckons you starred with her in Just William on the BBC Home Service around 1947

    Will you admit to you're past follies

    Ian

  7. #27
    Bob F.'s Avatar
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    Yes, it's all true: I am the secret love-child of Arthur Askey and Joyce Grenfell ...

  8. #28

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    Quote Originally Posted by Martin Reed View Post
    It was actually almost exactly 40 8x10"s before
    the developer was truly finished, ...
    You'd have had the same results testing with
    4x5 sheets and the appropriate amount of
    developer. What a waste. Dan

  9. #29
    Martin Reed's Avatar
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    We're talking 1973 here... attitudes to economy & resources have changed more than a little since then. But apart from that, I think it was a way of doing something useful with some stale paper.

  10. #30

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    Quote Originally Posted by Martin Reed View Post
    We're talking 1973 here... attitudes to economy & resources
    have changed more than a little since then.
    My comment was in retrospect; your assignment many
    years ago. So, who was instructing us other wise? Not
    that there were no thrift thinking sorts about only
    that they were not so numerous.

    Besides, there WAS plenty of every thing and NONE of
    it was ever going to run out. Now more and more
    share less and less. Dan

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