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  1. #21
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    Quote Originally Posted by Paul Verizzo View Post
    Yes, I know. But without extensive other stuff, visual clearing was the standard. And regardless of safety margins or other matters, all the fixers and variations were held at a constant. I was interested in one possibility compared to another, not the absolute correct answer. I think that my speed conclusions are the core results and that it would be difficult to change the ratings much by pH or other variables.

    The U-shaped curve is also in Haist, so that was my source of knowledge on that matter.

    I appreciate your return and thanking me for my work. I was taken a bit aback on your first comments.
    Paul;

    The comment about fix vs fix time was intended for those who don't know the difference. That was not a criticism, but it did explain why my numers, should I publish them would be different than yours and so would some others.

    I think it is a fine test. Keep it up.

    PE

  2. #22

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    Quote Originally Posted by Paul Verizzo View Post
    Of course, I wasn't addressing this at all........

    And my next line of thinking is why not put
    some steel wool in the stored fixer for the silver
    to latch onto? Probably too simple.)
    Not too simple. Very likely disastrously contaminating;
    the silver comes out of solution and iron enters solution.

    As for Film strength vs Paper strength, the subject
    was broached in the PDF as a question. Three frivolous
    reasons were given for there being two strengths. My
    previous post gave a least one GOOD reason for the
    two strengths and even a third strength. Paper
    strength, 1:7 or 1:9 may be an industry
    compromise. Dan

    AFAIK, Film strength for Paper was an Ilford invention.
    At the very least it was popularized by them as part
    of their Archival Processing Sequence; no longer
    mentioned. I've not found any reference by
    Kodak suggesting a 1:3 or 1:4 film
    strength for paper. Dan

  3. #23
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    It may be worth noting that according to some sources hypo and silver hypo complexes tend to bind to baryta. This is reported in the literature somewhere, but I have forgotten where I've read it.

    I have found that my coatings on plain papers of the same weight as the baryta I coat on seem to wash faster. If this is all true, then it might not be a wise thing to use a concentrated fix for FB papers. Just a thought.

    PE

  4. #24

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    Pondering...

    Quote Originally Posted by Photo Engineer View Post
    Paul;

    The comment about fix vs fix time was intended for those who don't know the difference. That was not a criticism, but it did explain why my numers, should I publish them would be different than yours and so would some others.

    I think it is a fine test. Keep it up.

    PE
    Yes, I should have used the phrase, "Time to Clear", instead of "Time to Fix."

    Too late for the copies that have gone out there, but I will change that when I have time.

    So, thanks for the constructive critique.

  5. #25

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    Paul --

    Just an observation, perhaps something to consider. If the ph is truely a concern, have you accounted for the fact that in most cases, (at least as far as I remember) one is going directly from the stop bath into the fixer. It would aoppear at least in my mind, that one would be dragging a fair amount of stopbath into the fixer, would that not lower the ph significantly?

  6. #26

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    Quote Originally Posted by Absinthe View Post
    Paul --

    Just an observation, perhaps something to consider. If the ph is truely a concern, have you accounted for the fact that in most cases, (at least as far as I remember) one is going directly from the stop bath into the fixer. It would aoppear at least in my mind, that one would be dragging a fair amount of stopbath into the fixer, would that not lower the ph significantly?
    Not if the Fixer is alkaline or neutral and is ph buffered.
    Tom Hoskinson
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  7. #27

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    Quote Originally Posted by Tom Hoskinson View Post
    Not if the Fixer is alkaline or neutral and is ph buffered.
    All I was suggesting was that when either going tray to tray or in a tank, there is some amount of stop bath left, and that is acidic right? Or is it towards ph neutral. I was not sure.

    So are the ph of the stop bath and fixer near the same?

  8. #28
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    I think that the point here is that it does not matter. Most fixers are buffered well enough to prevent pH swings whether alkali or acid is carried in. Even hypo itself has some buffer capacity, and hypo is one thing fixers have a lot of.

    PE

  9. #29

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    Ok, you've convinced me

  10. #30

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    Quote Originally Posted by Paul Verizzo View Post
    I hope I did this right......
    Looks Good to me, Paul. Excellent job! Thanks for doing it!
    Tom Hoskinson
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