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  1. #411
    Ian Grant's Avatar
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    Kodak state that a stop bath or water rinse is fine for films and we shouldn't forget that, it's fine in practice.

    Kodak also use no sto bath or water rinse in some maxchine processors for film and that should lay a few myths to rest, but a water rinse or staop bath is far better practice.

    Ian

  2. #412
    Steve Smith's Avatar
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    If the fix is not going to be re-used, is there any reason (real, not mythology) why a film can't go straight from developer to fix?


    Steve.

  3. #413

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    Several years ago a commercial lab improperly processed some film for me - pinholes that were likely due to too acidic a stop bath. For film I would think too drastic of ph changes could cause problems. If both developers and fixers are alkaline, a water rinse or even an alkaline stop (sodium metasulfite?) would be safer.
    Looked up in Anchell & Troop and suggested alkaline formulae appears to include sodium metaborate and sodium bisulfite. But can't find an exact formulae.
    Last edited by doughowk; 01-02-2013 at 06:48 AM. Click to view previous post history.
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  4. #414
    Steve Smith's Avatar
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    Another question: As we have both alkaline and acid fixers, is it possible to have a neutral fixer?


    Steve.

  5. #415
    Ian Grant's Avatar
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    Most alkaline fixers are closer to neutral and even fixers like Hypam & Ilford rapid fixer are only slightly acidic at pH 5.4. Black coffee is more acidic

    Ian

  6. #416
    Steve Smith's Avatar
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    Then why the fuss about fixers bleaching images? The users of staining developers are particularly fussy about this!


    Steve.

  7. #417

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    Quote Originally Posted by Ian Grant View Post
    Most alkaline fixers are closer to neutral and even fixers like Hypam & Ilford rapid fixer are only slightly acidic at pH 5.4. Black coffee is more acidic

    Ian
    dang!
    now i think i am going to start using "coffeeshop", black coffee stopbath together with sumatranol and seawater fixer i am
    all set for the next mayan apocalypse !

    thanks for the 411! ian

    drinking his arabica
    john

  8. #418
    Photo Engineer's Avatar
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    TF-5 is nearly neutral. In fact, it is the most nearly neutral of all B&W fixers.

    Going directly into the fix though carries developer into the fix which is not good, throw away or not! You have to remove as much of this junk as possible before you go into the fix so that the fixing action takes place in the absence of HQ, Phenidone, Metol and whatever else could be in there.

    The changes in pH have been there for ages. Early processes used a stop and had no real problems. Going from developer to acid stop to alkaline fixer certainly changes swell, but I have tested it and it works even with TF-4. And, no matter what you do, you will have changes in swell due to the ionic strength of the solution (or just water) and pH changes. After all, a ph 10 developer followed by a pH 6 city water rinse followed by a pH 8 TF-4 or a pH 4.5 Acid Fix certainly does not hurt anything.

    PE

  9. #419

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    Quote Originally Posted by Steve Smith View Post
    Then why the fuss about fixers bleaching images? The users of staining developers are particularly fussy about this!


    Steve.
    The pH per se is not reason why a fixer does or does not bleach the developed silver. As for staining developers, the conventional wisdom was that acidic solutions inhibit the formation of, or reduce the amount of stain. However I have still not seen proper tests that conclude either way. First there is the question as to whether the pH of the stop bath, fixer and wash water influence the degree of stain. Second, one must differentiate between the effects (if any) on general stain and imagewise stain. Third, it apparently depends on the developer formulation itself. For example Hutchings always said an acidic fixer and acidic wash water would reduce/inhibit stain with PMK (whether it is general or imagewise stain is a murky issue). Yet he does recommend an acidic stop bath. Some rigorous testing is definitely needed here. On the other hand, John Wimberley claims the full imagewise stain with WD2D/WD2H is formed in development and is stable thereafter, meaning you can use an acetic stop bath and aa regular acidic rapid fixer with no problem. He has done a fair bit of testing on this.

  10. #420
    Steve Smith's Avatar
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    The only staining developer I have used it Prescysol. It is advised to use an alkaline fix with this but I have seen no difference in my own negative with acid or alkaline.

    I'm sure if there was a reduction of stain with an acid fix, it would be dependent upon the time spent in the fix.


    Steve.



 

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