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  1. #11
    Photo Engineer's Avatar
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    There are several anti-clumping ingredients. I know that Sodium Silicate is used and (IIRC) Sodium Thiosulfate is used. Either has an effect on imaging. The Silicate can "dilute" the halide effect, and it can also fail to dissolve completely thus leaving a residue in the film. The effect of the hypo is obvious even at low levels.

    But, I am speaking more about emulsion making than processing. The effects are far more pronounced in emulsion making than in solution makeup. Still, there are effects in either.

    PE

  2. #12
    AndreasT's Avatar
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    For what does one use sodium chloride in a developer?
    By the way how long does benzotriazol last?

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    Quote Originally Posted by AndreasT View Post
    For what does one use sodium chloride in a developer?
    By the way how long does benzotriazol last?
    A. Iodized table salt is a ready source for potassium iodide, a very powerful restrainer. Whether the additives that PE expresses concern about would affect a developer and film one would have to experiment. It has been used for years for this purpose and some recent intertube explorations yielded no problems announced.

    B. "Forever." Like my potassium bromide, something like 25 years and doing just fine.

  4. #14
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    How powerful does powerful mean? How does one know how much to use?
    By experimenting?

  5. #15
    AgX
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    Quote Originally Posted by Photo Engineer View Post
    There are several anti-clumping ingredients. I know that Sodium Silicate is used and (IIRC) Sodium Thiosulfate is used. Either has an effect on imaging.
    In Germany (as alternative to Calcium or Magnesium Carbonate) Sodium, Potassium or Calcium Ferrocyanide is used in table salt.

  6. #16
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    Quote Originally Posted by AgX View Post
    In Germany (as alternative to Calcium or Magnesium Carbonate) Sodium, Potassium or Calcium Ferrocyanide is used in table salt.
    But from what I understand, at concentrations of less than 2%.

    “The contemplation of things as they are, without error or confusion, without substitution or imposture, is in itself a nobler thing than a whole harvest of invention”

    Francis Bacon

  7. #17
    AndreasT's Avatar
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    Isn`t all this posionous?

  8. #18

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    Quote Originally Posted by AndreasT View Post
    How powerful does powerful mean? How does one know how much to use?
    By experimenting?
    "Powerful" means, relatively, restraining action to the weight.

    A quick glance at some C-41 formulas shows, typically, about 1.5 grams of potassium bromide and 1.5 MILLIgrams of KI.

    The only practical way to measure that, even with something like my Ohaus Centrigram scale, is weigh out and put in water or alcohol, then use small measures from there.

    Glancing at the iodized salt labels, I see that some actually tell how many milligrams (or was it nanograms?) were in a serving. Good ole grocery store photochemicals. Salt, sodium carbonate posing as washing soda, borax, and in a less paranoid age, sodium hydroxide as drain cleaner.
    Last edited by Paul Verizzo; 02-11-2013 at 08:17 PM. Click to view previous post history. Reason: My brain malfunctioned and I called potassium iodide, bromide.

  9. #19
    AgX
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    Quote Originally Posted by cliveh View Post
    But from what I understand, at concentrations of less than 2%.
    Less than 0,002%.

  10. #20
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    Paul, I think you meant MILLIgrams of KI.

    And, the hypo is present in table salt to preserve the KI which decomposes into Iodate and Iodine.

    Why use table salt in a developer? For the KI present. To restrain slow Azo type emulsions, and also it is used in Microdol-X as a silver halide solvent, and is used in some fix formulas and wash aids!!!

    The Silicate is water soluble but can be retained as it is a large molecule and washes out slowly and the Iodide and hypo are not very good. Ferrocyanides can cause fog. So, it remains to be seen whether these can be used without harming your precious negatives. I don't use table salt for any purpose. I did the experiment one time and the result in making an emulsion was a disaster, as Silver Silicate formed as did Silver Iodide. The tiny amount of hypo also increased fog!

    PE

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