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  1. #21
    Ole
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    I use water with film, and with paper as well - except in the case of lith printing, where it's crucial that the development stops immidiately.

    If I use fixer it is citric acid, about 10-15 grams is one liter of water.

    Getting acid stop in an alkaline fixer shold not be a major problem. I use OF-1 (metaborate version) with citric acid stop, and have had no problems with lith prints. I would not use the bicarbonate version with an acid stop, nor would I use acetic acid stop with alkaline fixer.

    OF-1 should be well enough buffered to take the small amount of stop that clings to the paper.

    If the life of the fixer is shorter because I use water instead of stop, I have never noticed. But I mix new fixer frequently, preferring not to risk poor fixing for the sake of saving fixer. Film and the time to use it is far more valuable than fixer.
    -- Ole Tjugen, Luddite Elitist
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    You put 3 to 5 rolls of film through 1500ml of fresh fixer?
    And no more? I might do that but I use fixer very dilute.
    I think you are likely throwing a lot of good fixer down
    the drain. Dan

  3. #23

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    The Film Developing Cookbook, pg 103, suggests that a water stop bath will allow shadows to continue to develop (while highlighs do not) and can also enhance adjacency effects.

    Has anyone found this to be true ???
    Last edited by Joseph; 01-24-2005 at 08:56 PM. Click to view previous post history.

  4. #24
    Gustavo_Castilla's Avatar
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    I guess so how may rolls do you put trough?
    Gustavo Castilla
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  5. #25

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    Does that 1500ml of working strength contain 300ml of concentrate?
    I've found that 20ml of 60% in a solution volume of 500ml will
    completly clear a 120 roll of Pan F+. So I'd put 15 rolls
    through 300ml of concentrate, ONE-SHOT.

    You'll need to put a roll or two through and see how it goes.
    I'd give a roll 3 minutes constant agitation, then see if it's done.
    Test with a little exposed roll. That puts the silver load on the
    fix and the quantity of fix is then the "worst" case amount.

    The 20ml may actually be more than needed. I'll be doing some
    more tests in a few days. Dan

  6. #26
    Thomas Bertilsson's Avatar
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    Quote Originally Posted by Joseph
    The Film Developing Cookbook, pg 103, suggests that a water stop bath will allow shadows to continue to develop (while highlighs do not) and can also enhance adjacency effects.

    Has anyone found this to be true ???
    I guess the developer is more active in the highlight areas, and will exhaust faster there. There is a developing technique called the water bath method, which is used to lower contrast, where film is alternated between water bath and developer, 1 min in each, back and forth. In the water, the highlights will stop developing almost immediately, while it will take longer for the developer to exhaust in the dark values, which will effectively decrease contrast. Used only when extreme contrast is photographed.
    I guess it's along the same lines.

    - Thomas
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    "...the heart and mind are the true lens of the camera". - Yousuf Karsh

  7. #27
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    Quote Originally Posted by Joseph
    The Film Developing Cookbook, pg 103, suggests that a water stop bath will allow shadows to continue to develop (while highlighs do not) and can also enhance adjacency effects.

    Has anyone found this to be true ???
    No I have not tried it, It may work if the water was still, like stand or two bath developing, however if running water is used surely any developer left over in the emulsion would very quickly be washed away or diluted.
    Barrie B.

  8. #28
    Ole
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    Quote Originally Posted by Joseph
    The Film Developing Cookbook, pg 103, suggests that a water stop bath will allow shadows to continue to develop (while highlighs do not) and can also enhance adjacency effects.

    Has anyone found this to be true ???
    I wonder how this could be tested...

    Two identical films with identical exposure and identical processing - OK. Can do that.

    Then dump one in (still) water for 30 seconds, the other in (still) stop for 30 seconds. OK - can do that.

    Then fixing in separate baths of identical fixer for the same time. Sorry - no can do. ne emulsion has been acidified, and will react differently to the fixer for the first (crucial) seconds.

    Acidic rapid fixer tends to bleach the image slightly more than neutral to alkaline fixer does. This is especially obvious where there is least image - in the shadow areas of film and highlights of paper.

    How can you tell what is due to what? Whether one had "developed further" or one has "bleached back"?
    -- Ole Tjugen, Luddite Elitist
    Norway

  9. #29

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    Why don't you test your rapid fixer and see how fast it bleaches your neg - and if it is significant. Or why not use a neutral fixer for both films.

  10. #30
    Donald Qualls's Avatar
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    Or, for purposes of the test, why not simply use the same conventional acid fixer for both? If the question is about whether stop bath stops development faster than water, it's obvious it should -- acidifying chemistry that only works in an alkaline environment is faster than simply diluting it until you can't detect the reaction rate. What happens in the fixer should be pretty much the same (at least for the first negative in fresh fixer) after the stop or "water stop" step. If you're that concerned about it, give both negs a second bath in acid stop so they enter the fixer in the same condition.

    However, there are other considerations -- an acid stop used with a carbonate alkali developer runs a risk of gas generation damaging the gelatin, but once the stop (or short wash) is completed, there's still the question of whether to use acid fixer or neutral/alkaline fixer. It's been strongly asserted, with what seems good chemical basis, that neutral to mildly alkaline fixers and, indeed, an all-alkaline process are better for emulsion, but there may still be a need to precisely stop development.

    One suggestion I've seen is to use a lower pH stop bath with a buffer providing a reserve of acidity -- sodium acetate buffering an acetic acid bath will have lower pH than the common 1.3% acetic acid stop, yet has (potentially, depending on concentrations) much larger reserve of acidity against neutralization by alkali carried from the developer, and is less prone to form gas on reaction with carbonate (because it's less strongly acidic). In fact, I wonder if it might not be possible to use unacidified (and thus very mildly alkaline) straight sodium acetate solution as a near-neutral stop -- still stopping the development, but without an acid that can change the gelatin state.
    Photography has always fascinated me -- as a child, simply for the magic of capturing an image onto glossy paper with a little box, but as an adult because of the unique juxtaposition of science and art -- the physics of optics, the mechanics of the camera, the chemistry of film and developer, alongside the art in seeing, composing, exposing, processing and printing.

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