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  1. #11

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    I think the discovery of sodium thiosulfate as a fixer was THE giant leap in the development of photography. Prior to its use, photographic images simply faded away.

    Dave

  2. #12

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    In keeping with the "all from household products" gestalt of coffee developers, however, some people have made fixers out of fertilizers that contain ammonium thiosulfate. You probably can't get fertilizer at the grocery store, but at least it *is* a non-photo consumer product.

    -NT
    Nathan Tenny
    San Diego, CA, USA

    The lady of the house has to be a pretty swell sort of person to put up with the annoyance of a photographer.
    -The Little Technical Library, _Developing, Printing, And Enlarging_

  3. #13
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    OTOH, there are ways to stabilize the image from further change. You leave the Silver Halides in place and treat them with an agent that prevents any further "damage" from light. This was the entire tenor of B&W work done by Grant Haist before his retirement. He and a team of chemists devised an entire class of chemical stabilizers that created light insensitive silver salts and prevented any further change.

    The simplest and weakest (poorest) IIRC was Potassium Iodide. The best was a class of chemicals called Isothouroniums. Of course going this route defeats the purpose of making the process simple or making a process that uses common chemicals. I'm just saying.....

    PE

  4. #14

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    Could one use, or do something with, potassium metabisulphate to create a thiosulphate?
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  5. #15
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    You must NEVER use Potassium salts in fixers. This is an absolute NO NO! Nor should you use Calcium or Magnesium salts. Aluminum salts do not appear to do any harm though. These 3 salts have been shown to virtually poison the fixing reaction.

    As for making hypo, see this: On an industrial scale, sodium thiosulfate is produced chiefly from liquid waste products of sodium sulfide or sulfur dye manufacture.[1] In the laboratory, this salt can be prepared by heating an aqueous solution of sodium sulfite with sulfur. It is from the Wikipedia article on hypo.

    PE

  6. #16

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    Quote Originally Posted by Rick A View Post
    Thought process are good for all of us. Do not stop thinking or asking questions, it's how we learn.
    +1

    I have heard that sodium thiosulphate is available from pool supply companies or is the main constituent of one of the liquid pool products. Not quite "household", but close enough.

  7. #17

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    Well, I'm certainly learning
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  8. #18
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    Another fixing agent is P. Cyanide - used by wet-plate/tin-type purists.

    I think saline can be used to fix Silver Chloride (?) emulsions - but even then it doesn't work well.
    DARKROOM AUTOMATION
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  9. #19

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    I gotta get me on a chemistry course, sulphites, sulphates, halides, chlorides, chlorates... lets call the whole thing off... (sorry, just burst into a little bit of song there).

    :0)
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  10. #20

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    Quote Originally Posted by Nicholas Lindan View Post
    Another fixing agent is P. Cyanide - used by wet-plate/tin-type purists.
    Many early photographers successfully removed themselves from the gene pool. Darwin in action!
    A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.

    ~Antoine de Saint-Exupery

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