Sodium thiosulfate

Discussion in 'B&W: Film, Paper, Chemistry' started by eshotwell, Oct 13, 2009.

  1. eshotwell

    eshotwell Member

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    Simple question I hope...

    Can Sodium thiosulfate by used by itself as a fixer for pyro negatives (tri-x 320 sheets)? I have the crystals but have no idea how to mix it.

    edward@crgdirectories.com
     
  2. Ian Grant

    Ian Grant Subscriber

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    It can 240gm per litre of water. But it has no buffering capacity so isn't good for re-use.

    Ian
     
  3. eshotwell

    eshotwell Member

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    Thanks Ian. Is that the working solution?
     
  4. kompressor

    kompressor Member

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    Ian, I have Sodium sulfite in a large bag. Can i use that for some good?
     
  5. Ian Grant

    Ian Grant Subscriber

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    Yes you could about 15 gms, but usually acetic acid or Metabisulphite is added as well. Have a look in e the Formulae/Recent Chems sectiotion here or on Unblinkingeye.

    Ian
     
  6. Anon Ymous

    Anon Ymous Member

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    Isn't acetic acid or sodium metabisulfite added in case you want to use a hardener as well? If that's true, sodium sulfite is the only thing required to make it reusable.
     
  7. dancqu

    dancqu Member

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    Use It Straight

    That's all I use, film or paper, sodium thiosulfate unadulterated.
    I mix fresh for the session. I do know that it can be bottled for
    at least a few days storage but don't bother because there
    is nothing to it to have fresh at time of use.

    There two of the sodiums, anhydrous and the penta hydrate.
    Full strength, which I never use, calls for 240 to 250 grams
    of the penta or 150 to 160 grams of the anhydrous. You'll
    know which one you've got by a chilling of the solution
    on dissolving the penta.

    For a roll of 120 I use 16 grams of the anhydrous. That
    would be 25 grams of the penta. Slow but fresh each
    roll and when done, down the drain. Dan
     
  8. mike c

    mike c Subscriber

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    dancqu,is penta the crystals that look like rice grains , anhydrous is dried powder?

    Mike
     
  9. McFortner

    McFortner Member

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    Penta is the large crystals. Like Dan, it's all I use right now. About 2/3 of a cup per 2 liters of water. My average fix time is about 8 minutes (depending on clip test). Sure, it's not as fast as other fixers, but it's more friendly to the environment and my septic tank.

    Michael
     
  10. dancqu

    dancqu Member

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    Anhydrous

    Anhydrous finely granular, penta coarsely.
    The penta is about 1/3 water and endothermic.

    With prints I use sodium thiosulfate very dilute
    one-shot. Minimum solution volumes help maintain
    good chemical mileage and reasonable times.

    Works well when single tray processing; great where
    short of space. A BIG plus with prints and likely film
    is the very low levels of silver in the fix;
    'archival' levels. Dan
     
  11. Herzeleid

    Herzeleid Member

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    What happens to the PH if sodium thiosulfate is mixed with acetic acid, metabisulphite or sodium sulfate? Will it be good for pyro developed negatives then?
     
  12. mike c

    mike c Subscriber

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    rice fixer

    Thanks Dan,I'm just starting to use it now with selenium toning on advise from a printing class . All though still using Formulary T5 fixer for film.
     
  13. juan

    juan Subscriber

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    I mix TF-2 for pyro negatives - 240g sodium thiosulfate, 15g sodium sulfite, 10g sodium metaborate in a liter of water. This will keep for a good while.
    juan