Stop Bath Question

Discussion in 'B&W: Film, Paper, Chemistry' started by zenrhino, Dec 3, 2004.

  1. zenrhino

    zenrhino Member

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    As I understand it, stop baths are generally just acetic acid and water.

    In that case, why don't people just use dilute household vinegar?

    Hopefully I'm not re-dicovering the wheel here.
     
  2. ann

    ann Subscriber

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    you are and some people do.
     
  3. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member Moderator

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    Some people do use white vinegar. White vinegar is generally weaker than stop bath, and I suspect it may actually be cheaper to mix stop bath from concentrate than to use white vinegar.
     
  4. rbarker

    rbarker Member

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    Don't forget to add a sprig of dill to the vinegar stop bath. :wink:
     
  5. kwmullet

    kwmullet Subscriber

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    Cheaper still, I think, to use citric acid. No smell, either. Check threads elsewhere on apug for precise proportion, but I use 1tsp per liter. must be dumped after each session, since it's organic, but has great capacity and effectiveness. I don't miss the smell, either.

    I found citric acid in the bulk spice section of a local organic food store. I think well-stocked canning sections in groceries may have it as well.

    -KwM-
     
  6. titrisol

    titrisol Member

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    kodak stop bath ends up being cheaper than vinegar in the US

    Back in Ecuador I couldn;t buy acetic acid (drug precursor) so I used vinegar or citric acid (1 tsp/l)
    Many ither things can be used as a stop bath, most acid salts (bisulfates) would work as well.
     
  7. Dean Williams

    Dean Williams Member

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    Considering Kodak stop bath (16 oz size) makes eight gallons for about $6, it's probably one of the most economical stops available. Plus, it lets you know when it quits working without any testing needed.
     
  8. zenrhino

    zenrhino Member

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    So it can be used more than once? The one I use now (Ilford) says not to do that, and I sure hate to pitch something if I can get another $.12 out of it. =)
     
  9. zenrhino

    zenrhino Member

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    Now I just need to find a chemistry that's alkaline so I can use another readily available poison - lutefisk.
     
  10. titrisol

    titrisol Member

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    i don't reuse the stop bath, just use it for prints, and dilute small amounts of aacid at a time and go checking how it works.
     
  11. dancqu

    dancqu Member

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    Don't forget the water. After all acid stops generally have 49 parts
    water to one part acid. A short acid stop serves to give film or paper
    an overall acidity which it needs to maintain the acidity of an acid fix.

    Now days with hardener incorporated emulsions I've doubts of any
    need to maintain the acidity of an acid fix.

    By dilution water only "stops" quickly. Water only will inactivate
    developer in the emulsion as the ph drops towards neutral. Dan
     
  12. Dean Williams

    Dean Williams Member

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    Yes, you can use it 'til it stops working. I'm talking about Kodak indicator stop bath. It's yellow when you mix it, and when it's exhausted it turns purple(ish). Keep using it 'til it turns color, then toss it and mix up another batch. For the Kodak stuff, an ounce in a half gallon of water is the proper dilution. I've never used the Ilford stuff, so if that's what you're using, follow their directions.
     
  13. Adrian Twiss

    Adrian Twiss Member

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    I used to use citric acid stop bath. In fact, Anchell recommends the use of Citric Acid with certain Amidol developer formulae. I've gone totally alkali now (using TF3 fix) and now use a plain water bath for about 1 minute for prints.
     
  14. Nick Zentena

    Nick Zentena Member

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    4litres of 5% vinegar here costs between $1 and $2 Canadian. That will make 16litres of 1% stop bath.
     
  15. modafoto

    modafoto Subscriber

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    My recipe in the Recipes Section called ModaStop is exactly this. Please comment on my dilution if think it is too weak or too strong.

    Morten