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  1. #11
    Photo Engineer's Avatar
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    This fixer describes TF-4 to a "T". To get that information, go to the Formulary web site and look up the instruction sheet for TF4. It has all kinds of information.

    PE

  2. #12

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    Quote Originally Posted by Photo Engineer View Post
    This fixer describes TF-4 to a "T". To get that information, go to the Formulary web site and look up the instruction sheet for TF4. It has all kinds of information.

    PE
    Thank you. And not to steal the thread away from the OP, but I wonder how this fixer would allow safe ferrotyping with no hardener.
    http://stores.photoformulary.com/Det...ory=ALL&no=148

  3. #13
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    Easily, as today's papers are many times harder than older papers and so ferrotyping would only add to the gloss.

    PE

  4. #14
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    Quote Originally Posted by Michael R 1974 View Post
    Anchell makes the statement alkaline fixers wash faster than acidic ones. He doesn't really explain why other than to use laundry soap as an analogy, saying alkaline soap washed out of clothing fibers faster than an acidic detergent would. In Anchell/Troop the authors also cite faster washing as a benefit of alkaline fixers, although this is in relation to film, not paper (The Film Developing Cookbook).
    Note that neither Haist, nor probably the other authors were at liberty to disclose trade secrets, and alkaline fixers were once considered trade secrets. Haist does describe how F-6 improved on F-5 by raising pH just a notch to make archival washing possible while maintainung low pH for proper hardening. When Anchell and Troop write about alkaline fixers, you can assume they did the tests to make these claims, remember where the 'T' in Formulary's TF-4 and TF-5 comes from

    Generally it is hard to say how many sheets of paper one can process with a certain amount of fixer because not only does it depend on paper type, fixer dilution and stop bath carry over, it also depends on the amount of undeveloped silver in your images (think high key vs. low key image matter). You can fix a lot more AgCl than AgBr or AgI, so emulsion type (warm tone vs. cold tone) also makes a difference. If you have developer carry over, you might introduce potassium ions which supposedly have a detrimental effect on fixing. I would assume that published numbers on fixer capacity are conservative estimates that cover most cases of regular dark room work, and that retained silver tests are to be used by those who want to be 100% certain.

    And about Kodak color fixer with its pH of 6.5: the reason this pH is chosen is because dyes change their hue if pH is off, not necessarily because this pH is ideal for fixing.
    Trying to be the best of whatever I am, even if what I am is no good.

  5. #15

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    Quote Originally Posted by Rudeofus View Post
    Note that neither Haist, nor probably the other authors were at liberty to disclose trade secrets, and alkaline fixers were once considered trade secrets. Haist does describe how F-6 improved on F-5 by raising pH just a notch to make archival washing possible while maintainung low pH for proper hardening. When Anchell and Troop write about alkaline fixers, you can assume they did the tests to make these claims, remember where the 'T' in Formulary's TF-4 and TF-5 comes from
    Regarding F-5/F-6, again, these are hardening Na Thiosulfate fixers. The type of hardener also makes a difference. Still, the discussion in Haist regarding fixer pH and washing (spread throughout the fixation and washing chapters) seems inconclusive. There are parts indicating the washing of gelatin is improved as fixer pH is raised to the isoelectric point (still acid), increasing fixer pH far above the isoelectric point of gelatin may actually retard gelatin washing, the rate of gelatin washing was not materially different for a chrome alum hardening fixer pH 3 and F-24, etc. Then there's the paper base with FB papers - the rate of paper washing is the same within a fixation pH range, the rate of paper washing is not materially affected by fixer pH, the rate of paper washing is improved with swelling when an alkaline bath is used after fixation, etc.

    Regarding Anchell/Troop, I would not assume anything actually. Absolutely no evidence is presented to support any of the voluminous conclusions the authors make regarding a myriad of materials and chemicals. There are also plenty of incorrect statements, and conclusions I don't agree with. Sorry but I can't take everything Troop says at face value, and there are clear biases in those books.

    Until I see credible test data, I remain unconvinced of the benefits (besides no bleaching) of alkaline Ammonium Thiosulfate fixers vs otherwise similar acidic fixers from Ilford or Kodak. There are also potential issues with alkaline fixers related to how development is stopped.

  6. #16

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    Quote Originally Posted by Michael R 1974 View Post
    ...There are also potential issues with alkaline fixers related to how development is stopped.
    Such as?

  7. #17
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    Quote Originally Posted by Sal Santamaura View Post
    Such as?
    An alkaline fixer won't stop development ....
    Trying to be the best of whatever I am, even if what I am is no good.

  8. #18

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    Sal, for example if one only uses a water rinse in between developer and alkaline fixer, it needs to be quite thorough as development activity could restart in the fixer.

    Anyhow, my intention here is not to bash alkaline fixers so I apologize if any of it came off that way. I'm merely asking some questions. Statements have been made regarding the working properties of alkaline fixers vs acidic (non hardening) fixers in relation to certain tanning developers, wash times (film and paper), hypo clearing, the general desirability of all-alkaline processes, and fixing capacities. What do we really know? What is it based on?

  9. #19
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    Quote Originally Posted by Michael R 1974 View Post
    Regarding F-5/F-6, again, these are hardening Na Thiosulfate fixers. The type of hardener also makes a difference. Still, the discussion in Haist regarding fixer pH and washing (spread throughout the fixation and washing chapters) seems inconclusive. There are parts indicating the washing of gelatin is improved as fixer pH is raised to the isoelectric point (still acid), increasing fixer pH far above the isoelectric point of gelatin may actually retard gelatin washing, the rate of gelatin washing was not materially different for a chrome alum hardening fixer pH 3 and F-24, etc. Then there's the paper base with FB papers - the rate of paper washing is the same within a fixation pH range, the rate of paper washing is not materially affected by fixer pH, the rate of paper washing is improved with swelling when an alkaline bath is used after fixation, etc.
    I believe that alkaline fixers swell gelatine faster and therefore allow faster fixation to archival standards. This means the paper needs to spend less time in fixer and therefore the paper base picks up less Thiosulfate which in turn helps during washing. Contrary to what you wrote multiple times I believe that gelatin is least swollen at its isoelectric point, therefore raising pH above that point would increase fixing and washing rate.
    Quote Originally Posted by Michael R 1974 View Post
    Regarding Anchell/Troop, I would not assume anything actually. Absolutely no evidence is presented to support any of the voluminous conclusions the authors make regarding a myriad of materials and chemicals. There are also plenty of incorrect statements, and conclusions I don't agree with. Sorry but I can't take everything Troop says at face value, and there are clear biases in those books.
    Neither Anchell nor Troop ever developed an emulsion, therefore they may not be authorities in that regard. As much as the comments on T-grain emulsion and photographic emulsions may contain erroneous, opinionated or incorrect statements, I would consider his chapters on developers and fixers sound. If one sells fixer recipes to Formulary, he better be on top of this stuff as there is little room for snake oil in the analog market. Neither author owes us data charts or lab notes from when they tested and formulated fixers, and screaming "Their books are *&$§!" will rather drive them away from us (as it just so happens, Bill Troop hasn't been on APUG for ages) than make them give us their privately and at their own expense obtained data records.
    Trying to be the best of whatever I am, even if what I am is no good.

  10. #20

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    Quote Originally Posted by Rudeofus View Post
    Contrary to what you wrote multiple times I believe that gelatin is least swollen at its isoelectric point, therefore raising pH above that point would increase fixing and washing rate.
    I didn't say the isoelectric point/pH had anything to do with gelatin swell. The discussion in Haist regarding the isoelectric point has to do with the affinity for thiosulfate and silver thiosulfate complexes.

    Swell is discussed from a diffusion perspective.

    With respect to The Film Developing Cookbook, it is a good book. I never said it was no good. But I can't agree everything they say about developers and fixers (developers in particular) is necessarily sound.

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