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  1. #11

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    I am a longtime user of TF-4 to reduce DR odor, improve workflow and toning. I toyed with the idea of using a weak stop; just in case. But what is the modern case for using a stop bath for prints?

    J Lootens, On Photographic Enlarging and Print Quality (1967) recommends a stop bath when using an acid-hardener fix. Hardeners were required if drying on ferrotype plates. kodak/Ilford recommend stop baths to prevent stains and assist in preserving the typical acid fix. But today, I think we can avoid acid stops with film, and with more care, processing fiber prints.
    RJ

  2. #12
    bruce terry's Avatar
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    Deep tray of water and 45 seconds of agitation is all the stopping TF-4 needs. Great stuff.

  3. #13

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    Quote Originally Posted by Photo Engineer View Post
    ... nor have I heard of any problems from Grant
    Haist who originated the idea.PE
    Clyde Hornacker is the original originator. It was in 1857,
    a few years after it was found that sodium thiosulfate would
    'fix out' silver halides, that he tested an alkaline fix and found
    that it worked better. I don't recall the source so can not quote.

    The story is he was treating a case of acid-indigestion and
    spilled some bi-carbonate of soda in the fix. The alkaline
    fix was born. Another one for Ripply's. Dan

  4. #14
    Photo Engineer's Avatar
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    Dan;

    Thanks, I was referring to his entire publication of the idea and theory which kicked off Bill Troop's research which lead to TF-4. Of course others have worked on alkaline fixes. In fact, alkaline fixes were used by Kodak in X-Ray and in the P-122 process years before Haist published.

    He was the one that explained the reasons for wanting an alkaline fix, namely increased swell and reduced wash times.

    The fix came long before Hornacker IIRC. It was done by Sir Humphrey Davey due to his work on both photography and on thiosulfates:

    http://www.rleggat.com/photohistory/history/davy.htm

    Hornacker had no clue as to what he had though if the reference is indeed correct. It took work in the mid 20th century to describe things properly.

    PE

  5. #15

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    Quote Originally Posted by Photo Engineer View Post
    Hornacker had no clue as to what he had though if
    the reference is indeed correct. It took work in the
    mid 20th century to describe things properly. PE
    Perhaps there was a Mr. Hornacker and more did
    test an alkaline fix some 100 years ago. If only he
    had kept records and afterwards they been saved
    and published. Then again film and papers
    have changed. Dan

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