Stop Bath Question

zenrhino · Dec 3, 2004

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.

ann · Dec 3, 2004

you are and some people do.

David A. Goldfarb · Dec 3, 2004

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.

rbarker · Dec 3, 2004

Don't forget to add a sprig of dill to the vinegar stop bath.

kwmullet · Dec 3, 2004

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-

titrisol · Dec 3, 2004

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.

Dean Williams · Dec 3, 2004

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.

zenrhino · Dec 3, 2004

Dean Williams said:
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.

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. =)

zenrhino · Dec 3, 2004

rbarker said:
Don't forget to add a sprig of dill to the vinegar stop bath.

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

titrisol · Dec 3, 2004

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.

dancqu · Dec 3, 2004

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

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

Dean Williams · Dec 4, 2004

zenrhino said:
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. =)

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.

Adrian Twiss · Dec 4, 2004

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.

Nick Zentena · Dec 4, 2004

Dean Williams said:
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.

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

modafoto · Dec 4, 2004

kwmullet said:
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-

My recipe in the Recipes Section called (there was a url link here which no longer exists) is exactly this. Please comment on my dilution if think it is too weak or too strong.

Morten

Stop Bath Question

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