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  1. #31

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    Having followed this scholarly treatise on print washing, understanding most of it, I have a question from the point of view of the Kodak customer--the guy who just buys (bought) the products on the camera store shelf. And I'm bound to ask if the washing instructions Kodak gave 40 years ago aren't still adequate today. Those instructions being Dektol, ISB, Kodak Fixer, HCA or Perma Wash, then an hour or so of washing in a rotary washer, for DW paper. Is there really that much advantage in the alkaline fixer and trying to flush out mere molecules worth of hypo for all that procedure? At some point, the image will either fade, dry and flake off, or the paper underneath it will turn to dust, whichever comes first. Is there really such an advantage in this hair-splitting procedure?

  2. #32
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    Quote Originally Posted by Michael R 1974 View Post
    I haven't said anything about fix rate, just wash rate. I don't know what I have backwards regarding pH and swell. If you're referring to the longer diffusion path slightly slowing down the washing of the emulsion layer as swell increases, I'm just pointing out it does say that in the text. The only definitive reference to an alkaline pH increasing wash efficiency is in the section on alkaline baths which I cited above. I guess what you're saying is the effect of an alkaline bath can essentially be combined with the fixing process in an alkaline fixer. Fair enough I guess.
    Michael, you keep quoting Haist's book as if it was a comprehensive collection of everything he knew about photochemistry. It simply isn't and Ron already told you why it couldn't. There is a long chapter on miracle tricks how to boost film speed by two stops, but besides its historical value there is little merit in that whole chapter. Many other chapters are outdated , incomplete or even misleading because of the restrictions Kodak forced onto Grant Haist. Think about the following facts:
    • The first edition was published in 1979 with the title "Modern Photographic Processing"
    • C41 was introduced in 1972, yet the book only mentions C-22
    • E6 was introduced in 1976, yet the book doesn't mention it
    • HC-110 was introduced in 1965, yet the book doesn't mention it

    The list could go on and on. And rest assured that Grant knew all these things very well considering his position!

    Fact is there is no easy to follow book or path into photochemistry, and a lot of research will have to be replicated by us or will be lost eventually.
    Trying to be the best of whatever I am, even if what I am is no good.

  3. #33
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    Quote Originally Posted by Tom1956 View Post
    At some point, the image will either fade, dry and flake off, or the paper underneath it will turn to dust, whichever comes first. Is there really such an advantage in this hair-splitting procedure?
    The limiting factor for my prints will likely be the garbage incinerator that my pics will be subjected to when I kick the bucket. There are, however, people who can make prints which mankind would like to last for a very long time, and most of the research on archival printing targets exactly these prints. It is up to every one of us for ourselves to decide how much effort we would want to put into making our prints archivally stable.
    Trying to be the best of whatever I am, even if what I am is no good.

  4. #34
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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
    I looked and couldn't find it. Well actually I was looking for information on T-5. I can find the listing for T-5 but not any washing information.

  5. #35

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    Quote Originally Posted by Photo Engineer View Post
    This is where you are wrong. You equate this to swell, wash time and charge. Charge does go down as pH goes up, but swell goes down as does diffusion.

    Photography is full of chemistry, and the best I can say is that there is a lot of bad or approximate information out there.

    PE
    I did not equate anything relating to the isoelectric point with swell. The discussion in Haist specifically regarding the isoelectric point has to do with charge influencing the retention of thiosulfate and silver thiosulfate ions, in relation to washing. I cited this clearly.

    All I was saying (with references) was that there appear to be various mechanisms and variables involved, and that they do not all necessarily move in the same direction.

  6. #36

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    Quote Originally Posted by Rudeofus View Post
    Michael, you keep quoting Haist's book as if it was a comprehensive collection of everything he knew about photochemistry. It simply isn't and Ron already told you why it couldn't. There is a long chapter on miracle tricks how to boost film speed by two stops, but besides its historical value there is little merit in that whole chapter. Many other chapters are outdated , incomplete or even misleading because of the restrictions Kodak forced onto Grant Haist. Think about the following facts:
    • The first edition was published in 1979 with the title "Modern Photographic Processing"
    • C41 was introduced in 1972, yet the book only mentions C-22
    • E6 was introduced in 1976, yet the book doesn't mention it
    • HC-110 was introduced in 1965, yet the book doesn't mention it

    The list could go on and on. And rest assured that Grant knew all these things very well considering his position!

    Fact is there is no easy to follow book or path into photochemistry, and a lot of research will have to be replicated by us or will be lost eventually.
    I'm not disagreeing. It is complex and I understand even in Haist's case there was a lot he could not say. I was merely trying to find some supporting evidence - theoretical or experimental - for the blanket claims made by people regarding the favourability of alkaline fixers. It seemed to me it is a little less straight forward than "pH up = washing time down". If Ron is saying that is sound, I am ok with it. But I still haven't seen any data on relative washing times for commercial products such as TF-4, or non-commercial formulas. Obviously I don't have every book or article, which is why I was asking the question.

    Sorry this got ugly. It was not my intent.

  7. #37
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    Quote Originally Posted by Michael R 1974 View Post
    I'm not disagreeing. It is complex and I understand even in Haist's case there was a lot he could not say. I was merely trying to find some supporting evidence - theoretical or experimental - for the blanket claims made by people regarding the favourability of alkaline fixers. It seemed to me it is a little less straight forward than "pH up = washing time down". If Ron is saying that is sound, I am ok with it. But I still haven't seen any data on relative washing times for commercial products such as TF-4, or non-commercial formulas. Obviously I don't have every book or article, which is why I was asking the question.
    I am afraid there is no publicly available data on this or it would have been posted here (or elsewhere) already. Since test kits for retained Silver Halide and retained Thiosulfate are readily available, it should take little effort to do some test runs at different pH values for both fixation and washing. Care is advised when chosing the compounds for lowering or raising pH as they might interfere with fixation themselves.
    Trying to be the best of whatever I am, even if what I am is no good.

  8. #38
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    I understand Michaels concern.
    Possible one could test ones own working materials. I for one would trust my own testing, but I would love to see some real “official” published materials concerning Alkaline Fixer.
    It would make me sleep better.
    I know that Maco who sells a neutral fixer (which formula I do not know) say you can wash the print in 16min.
    8x2 min continues rocking in a tray.
    That is short.
    I have not asked them how they get to this short time.

  9. #39
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    Quote Originally Posted by Photo Engineer View Post
    This is where you are wrong. You equate this to swell, wash time and charge. Charge does go down as pH goes up, but swell goes down as does diffusion.

    Photography is full of chemistry, and the best I can say is that there is a lot of bad or approximate information out there.

    PE
    This should be corrected to read:

    "Positive charge does go down as pH goes up and negative charge goes down as pH goes down. But, as pH goes up, swell goes up and as pH goes down, swell goes down. As swell goes down, diffusion goes down.

    This should clarify my quoted post.

    PE

  10. #40
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    Roger, it is TF-4 and TF-5. The information for each is a pdf file under tech info.

    See here: http://stores.photoformulary.com/ima...n1/03-0141.pdf


    Tom, since Kodak no longer makes B&W paper, their instructions are moot in the sense that they have no modern papers and no R&D unit to run tests. However, their tests do hold up. Hypo never reaches zero. Haist shows that both Hypo and Hydroquinone are retained and contribute to keeping problems and thus must be removed to an archival level. Mason gives the math behind this process. You can never reach zero though. But you can overwash, especailly RC paper. See the article by Ctein.

    PE

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