Testing XTOL...

Discussion in 'B&W: Film, Paper, Chemistry' started by ChristopherCoy, Oct 31, 2012.

  1. ChristopherCoy

    ChristopherCoy Member

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    Is there a way to test and see if XTOL is still good?

    I mixed some up around the beginning or mid part of July, when I got my F100 and was testing it out. I have not developed a roll since then. The XTOL was newly mixed, and has sat in a black jug in a cabinet in the utility room ever since then.

    I have two rolls that I need to develop, but I don't want to risk the XTOL being bad.
     
  2. Gerald C Koch

    Gerald C Koch Member

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    Clip off the leader of one of the two films and dip it in the Xtol. If it turns dark then the developer is probably OK.
     
  3. Photo Engineer

    Photo Engineer Subscriber

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    Gerry, Christopher, this dip test can fail as well. You see, as the developer fails, it can still give a black leader but the time to achieve that blackness may vary and thus the film can come out thin if the Xtol is going bad.

    The only way to test reliably is to run the leader test fresh and time the time to black and then when you want to use it check the time against the fresh test. It should vary only by seconds, say 30" max or it is bad.

    PE
     
  4. albada

    albada Member

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    Another test is similar: Develop a piece of leader the same way (time, temperature, agitation) as you would the normal film. You can do this in light. Stop, fix and wash as normal. Because of the extra circulation it gets when alone in the beaker, the result should be more dense than a leader developed with the roll. Compare your test-leader with a normal one, and if it's denser, the XTOL is probably okay.

    Mark Overton
     
  5. ParkerSmithPhoto

    ParkerSmithPhoto Member

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    If the jug was full or mostly so, it should be perfectly fine. I mix stock and then divide it into 500mL amber glass bottles full to the top. My last batch lasted 7 months (not shooting enough film, obviously) with no problems.

    The 500mL bottles are from USPlastic.com and I've started using them for all developers. Keeps it nice and fresh during the extended absences.
     
  6. brianmquinn

    brianmquinn Member

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    From
    http://www.covingtoninnovations.com/xtol/

    Making Sure Your Xtol Hasn't Gone Bad
    Because Xtol does not turn brown when oxidized, you can't tell whether it has gotten too old by just looking at it. Here are two simple tests you can use instead.
    Clip test
    This can also be used to determine an approximate developing time for an unfamiliar kind of film.
    Cut off a small piece of the film and develop it in full room light, using the development time you consider most likely to be correct. Wash it in water, fix it in fixer, wash it again, and let it dry.
    Then compare your sample to the fully exposed end of a correctly developed roll of the same or similar film. Your sample should be almost but not quite black; strong lights should be visible through it. If it's not very dark, increase development or mix fresh developer; if it's pitch-black, use a shorter developing time.
    Paper test
    This is a very quick way to determine that your Xtol stock solution still works. You'll need a small scrap of photographic paper that doesn't have a developing agent incorporated; I use Ilford Multigrade IV RC, but many others work just as well. Try the test with a known good sample of developer before relying on it.
    To perform the test, expose the paper to full room light (white light, not safelight) and put a drop of Xtol on it. Then, 30 seconds later, put another drop of Xtol on it in a different place. After 30 more seconds, rinse the paper under running water and put it into the fixer, then wash and dry as usual. The first spot should be dark gray, and the second one, medium gray. After fixing they will be quite warm-toned.