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  1. #291
    Ian Grant's Avatar
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    We don't disagree about that, the issue was what part a stop bath played in it, and it seems both Kodak & Fuji think none at all as they leave the entire stage out.

    My feeling is that potential HQ Metol retention issues are far greater when films and papers are processed mechanically where every stage is kept close to the minimum time limits. Kodak didn't use a stop bath with their RT processing machines either. You pointed out the effects on colour papers in the 70's and this may be another potential issue particularly with wash-less colour film & paper processors.

    However as we are talking home processing, or decent monochrome labs then I'd be fairly certain that our stop bath or alternative rinse, longer fixing & washing times will takes us way lower than the Kodak, Fuji RT systems, which they seem to think are good enough.

    Ian

  2. #292
    Photo Engineer's Avatar
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    The problem is, Ian, all R&D at EK stopped with regard to B&W processes in about 1985 or thereabouts. As the effect of having developing agent retention and thus worse image stability was known but not worked out for home use or even well understood except in color, not much was said about it or done about it. I do know that HQ and Metol are hard to remove and I do know that Metol is rendered more soluble by acid. So, it is harder to remove if you omit a stop and use an alkaline fix. If you use a stop, much of the Metol can be removed in the stop.

    As for HQ, it is more easily removed in alkaline solution or if it is Sulfonated, so a Sulfite containing stop can assist in removal of HQ. Thus, I made the statements I did about the utility of stops in general. They can help in this regard.

    The current wisdom at Kodak was to keep the current recommendations for use of a stop and if the wash was good enough and had a safety margin, then the film and paper were ok. The problem is that AFAIK Kodak only ran release tests for B&W products in an acid fixer with and without hardener. IDK what Ilford used!

    Nowdays, neutral and alkaline fixers are becoming more prevalent. This changes the playing field and I have said that I have no method to test for retained developing agent.

    Therefore, I take the route of caution and made the statements I did regarding B&W products because I knew the chemistry involved and the internal test results. Regarding color, neither Metol or HQ is used is used in color and the bleaches are acidic enough. However, in color paper a stop should be used.

    PE

  3. #293
    Ian Grant's Avatar
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    Research might have stopped Ron but the materials have been around rather a long tome now, silver gelatin negatives nearly 140 years. FP4 is is 55 years old, Tri-X over 70 so if we were going to see problems they'd have occurred by now. That's why I think you're alarmist, fixers contain Sulphite and/or Metabisulphite which aids fixing and removal of silver thiosulphate complexes so HQ & Metol as well.

    You make a point about acidity and metol and sulphite all conditions met in Ilford & Kodak's rapid fixers.

    So a greater issue arises when someone uses an Alkaline fixer because those criteria aren't being met. I know you advise an acid stop bath but many don't use one so could have major problems particularly with FB prints if what you theorise occurs.

    Only yesterday on another forum someone said an acid stop bath was a no no with alkaline fixers. I did say you advised differently.

    Then we need to look at just how much developer is adsorbed & used there are figures for how much is taken from solution, and how much is actually used to develop a given area of film. So after a stop bath or rinse we are looking at very low levels left in the film anyway. I have some data on that relating to when Ilford were testing their PQ version of ID-11/D76 (which became Autophen) to determine replenishment rates.

    Ian

  4. #294
    Ian Grant's Avatar
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    Quote Originally Posted by Sirius Glass View Post
    It is really pretty simple.

    Stop bath is cheap and reusable.

    If water is used instead of stop bath, the life of hypo is shortened and fogging may occur.
    No-one has said that except you


    Quote Originally Posted by Sirius Glass View Post
    Stop bath should not be used with some developers. Pyro needs an alkaline archival fixer such as TF4 or TF5. Example, Rollo Pyro developer should not have stop bath used because it needs a fixer like TF-4 or TF-5 after a water wash.
    Steve
    You can use a weaker stop bath with Pyro developers and also fixers like Hypam and Ilford & Kodak Rapid fixers. That's what many do including Sandy King


    Quote Originally Posted by Sirius Glass View Post
    Can you use water instead of stop bath for non-pyro developers? Sure, but then again your photographs are probably not worth protecting anyway. :o :o :o

    Steve
    You shouldn't talk about your negatives like that Steve

    More seriously the use of stop bath with films only began more widely in the 1930's with the big take up of 35mm in Europe.

    There's many great negative that never saw a stop bath, it's pure speculative conjecture based on no evidence at all that there could be a difference.

    Ian

  5. #295
    Thomas Bertilsson's Avatar
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    "Often moments come looking for us". - Robert Frank

    "Make good art!" - Neil Gaiman

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

  6. #296

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    Wait!
    Shouldn't you flog (not beat) a dead horse?

  7. #297
    Ian Grant's Avatar
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    Should have clarified the fogging bit for you Steve and highlighted the last part of the 3rd sentence, - fogging: that's been pure conjecture, all the companies used water for years with NO issues, and still say you can.

    You'll find I've consistently said a stop bath or water rinse will prolong the life of a fixer (stop more so), and that a stop bath arrest development faster

    There's been to many unfounded claims based on no facts at all that a water rinse doesn't work properly as a replacement for stop bath, when processing a film.

    So no mistakes on my part. I commented on what you wrote, not earlier posts.

    Steve Smith was talking using no rinse or stop bath, adding the fix immediately so that comment of mine is out of context when talking about using either water or a stop bath.

    One could question your motives for deliberately restirring flames. Ron & I agree that water can be used instead of stop bath.

    Ian
    Last edited by Ian Grant; 07-23-2010 at 03:28 PM. Click to view previous post history. Reason: add

  8. #298
    Ian Grant's Avatar
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    I agree Thomas

    Ian

  9. #299
    Thomas Bertilsson's Avatar
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    See if you can find an animated gif for that one...

    Quote Originally Posted by Q.G. View Post
    Wait!
    Shouldn't you flog (not beat) a dead horse?
    "Often moments come looking for us". - Robert Frank

    "Make good art!" - Neil Gaiman

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

  10. #300
    clayne's Avatar
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    So we all agree then: water is not the best choice? :-D
    Stop worrying about grain, resolution, sharpness, and everything else that doesn't have a damn thing to do with substance.

    http://www.flickr.com/kediwah



 

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