What stop bath do you use?

[j._patric_dahl_n]

I just use a little acetic acid (24%) in the water to make stop baths. I don't bother to messure...

 

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Do you buy your stop bath, use glacial acetic adic or maybe citric acid?

 

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Here are two Agfa recipes:

 

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Stop Bath for paper, Agfa 200:

 

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Glacial Acetic Acid (99%) - 20.0 ml

Cold water to make - 1.0 liter

 

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Stop Bath for films, Agfa 201:

 

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Potassium Metabisulfite - 40.0 grams

Cold water to make - 1.0 liter

 

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Potassium Metabisulfite? This must be an expensive stop bath to use, and why this chemical?

[ed b.]

I start with glacial acetic acid because it is cheap. I mix it down

to a 28% solution by adding 3 parts acid to 8 parts water. Then I

add 1.5 oz of 28% acetic acid to a quart of water (or 45ml to a

liter) for my working solution.

 

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I no longer use an acid stop bath for most films. Instead, I rinse in

tap water--four complete changes of water over a minute to a minute

and a half. If I do decide for some reason to use an acid stop bath,

I always give the film a water rinse first.

 

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In regard to your question about the metabisulfite stop bath, the

chemical, though essentially a salt, has a slightly acidic reaction,

and so makes a good mild stop bath. It is probably less likely to

cause pin holes in negative emulsions if you don't use a water rinse.

[cesar_barreto]

Patric,

Metabisulfite and acetic acid can both smell too much within the

walls of darkroom, mainly on trays. Citric acid can also be used, at

10/20%, making your life somewhat more comfortable in the dark.

All those chemicals are inexpensive and not so necessary with films,

as they usually don't carry over much developer. Fiber paper, in the

opposite side, can spoil fixer much faster if a stop bath doesn't

come for help. Wich acid soap does the trick, usually doesn't make

much difference.

Good work.

 

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Cesar B.

[christian_harkness]

For prints I use water.

 

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chris

[joe_miller2]

Ilford recommends that you don't use a stop bath because of the

possibility of pin holes.

[j._patric_dahl_n]

I have had problems with pinholes on Efke films, but I thought that

was because of the agitation. Efke film has a very thin layer of

emulsion. Hmmmmm, maybe I should try a plain water stop bath in the

future with these films?

[christian_harkness]

Hey, that should have been 'for film I use water'! Duhhhhhhhh

 

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chris

[raja_a._adal]

For those who use water, how many changes? Since I don't have

running water in my darkroom, is there any disadvantage to using just

one 1 minute water bath with agitation (other than killing the fix

more quickly)?

[robert_orofino1]

I use Kodak Indicator Stop Bath at 1/2 the recommended dilution

(approximately 7ml per liter)& discard after use. No pinhole problems

on film and it lasts an entire printing session.

[pete_andrews]

Potassium Metabisulphite is a very cheap chemical. It's widely used as

a preservative and cleaner in winemaking, brewing and other food

preparation, and is available in convenient tablet form. It forms

Sulphurous acid in solution, the same acid as in Fixing baths, hence

the same pungent smell. This also makes it totally compatible with

normal acid fixing baths<p>Pinholing is caused by carryover from the

developer outgassing within the emulsion. The main culprits are

developers with a high carbonate content, and higher than normal

processing temperatures. The carbonate breaks down to give off carbon

dioxide in any acid solution.<br>The 'cure' would be to use a two bath

stop, the first plain water, and the second a weak acid bath to

prolong the life of the fixer. This kind of defeats the secondary

purpose of the stop bath, which is to rapidly arrest the development.

[christian_harkness]

I am not sure on how many changes of water, if you don't have running

water. However I believe as long as you are consistent in what you

do, you will be ok. For starters I would try a couple of changes of

water and letting it sit for a couple of minutes at least. Be sure

you monitor your fixer.

 

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chris

[scott_walton1]

I have used Kodak's indicator but didn't like the smell all that much,

went to Sprint's Stop which is vanilla scented and that was great for

awhile but usually now it's just citric acid and change often.

Cheers,

Scott

[celcio]

changes of water? every 30-40 secs of continous and strong agitation,

 

during 2 mins.