Using Acetic Acid to make stop bath

VirtualAdept

VirtualAdept

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Mads
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Afternoon all, I'm hoping you can help me with this one before I post another printing question later...

I've got some acetic acid that'll make up 500ml @ 80%.
What sort of dilution am I looking at to use as stop bath for printing?
I read somewhere it needs to be something like 3% acetic acid to work as stop bath, but I wanted to check with sources that I actually trust, ie, you lot :D

Thanks in advance
Mads
 
I never found stop bath usefull and have always just washed in plain water. However I looked this up in my old books and the Rollei Manual 3rd edition from 1957 suggests 1 ounce glacial Acetic Acid plus water to make 80 ounces of solution which is roughly 20 milliltres of acid plus water to make it up to 1 litre of working solution.

To be honest, it's far better to get into the habit of exposing prints so that you can develop to extinction. In other words: you should be able to leave the paper in the dish much longer than the recommended development time without it going darker than you want.
 
VirtualAdept said:
Afternoon all, I'm hoping you can help me with this one before I post another printing question later...

I've got some acetic acid that'll make up 500ml @ 80%.
What sort of dilution am I looking at to use as stop bath for printing?
I read somewhere it needs to be something like 3% acetic acid to work as stop bath, but I wanted to check with sources that I actually trust, ie, you lot :D

Thanks in advance
Mads
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I'd dispose of this properly and buy a commercial stopbath instead.
 
Whilst I agree with Andrew about exposing prints so that you can develop to extinction (this is always the way to get best gradation), the stop bath also neutralises the alkali developer and, hence, extend the life and effectiveness of the fixer.
 
I seem to recall it’s a 2% solution for RA4 prints, so likely okay for B&W too.
 
AndrewFlannigan said:
I never found stop bath usefull and have always just washed in plain water. However I looked this up in my old books and the Rollei Manual 3rd edition from 1957 suggests 1 ounce glacial Acetic Acid plus water to make 80 ounces of solution which is roughly 20 milliltres of acid plus water to make it up to 1 litre of working solution.

To be honest, it's far better to get into the habit of exposing prints so that you can develop to extinction. In other words: you should be able to leave the paper in the dish much longer than the recommended development time without it going darker than you want.
Click to expand...



yzfmike said:
Whilst I agree with Andrew about exposing prints so that you can develop to extinction (this is always the way to get best gradation), the stop bath also neutralises the alkali developer and, hence, extend the life and effectiveness of the fixer.
Click to expand...


Thanks guys, I'll look into that. I've not heard of doing that before.

FujiLove said:
I seem to recall it’s a 2% solution for RA4 prints, so likely okay for B&W too.
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Righto, thank you
 
It's no big deal to make a bit of stop solution, and I'm sure the concentration isn't super-critical, just as long as it's not too weak or strong & mess up the pH of the fixer. The smells are all part of the 'charm' of hand printing mono.

AndrewFlannigan said:
I never found stop bath usefull and have always just washed in plain water. However I looked this up in my old books and the Rollei Manual 3rd edition from 1957 suggests 1 ounce glacial Acetic Acid plus water to make 80 ounces of solution which is roughly 20 milliltres of acid plus water to make it up to 1 litre of working solution.
Click to expand...

FujiLove said:
I seem to recall it’s a 2% solution for RA4 prints, so likely okay for B&W too.
Click to expand...

A fluid ounce is about 25ml, so that's 25ml of acid in 2 litres of water or 1.25%. You can probably make it a bit stronger if you wanted as Fujilove suggests, and add 40ml per 2L.
 
Be extremely careful of glacial Acetic Acid - it's almost as corrosive as pure Sulphuric Acid - if you plan to mix it use rubber gloves and eye protection and PLENTY of ventilation.
 
I wouldn't risk it. If you get it wrong you may harm the film. I'd suggest you either buy proper shop bath or just use water, which I did for years.
If you still want to try Ilford suggest
Acetic acid glacial 1 fl ounce, water to make 80 ounces (17cc to make a 1000cc)) from the ilford manual of photography 1958.
 
If you are worried about handling glacial acetic acid (which a] pen and inks b] is nasty if it splashes in eye) nip down to local supermarket and buy distilled white vinegar which is 5% acetic acid - dilute 1 part vinegar to 4 parts water to give you a 1% solution.
 
petersmart said:
Be extremely careful of glacial Acetic Acid - it's almost as corrosive as pure Sulphuric Acid - if you plan to mix it use rubber gloves and eye protection and PLENTY of ventilation.
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Agreed. I always dilute mine down to 10% and store it that way. I’d also recommend handling it outdoors if you can as the fumes are not good for the lungs.
 
dmb said:
If you are worried about handling glacial acetic acid (which a] pen and inks b] is nasty if it splashes in eye) nip down to local supermarket and buy distilled white vinegar which is 5% acetic acid - dilute 1 part vinegar to 4 parts water to give you a 1% solution.
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I must admit I've done that, but wasn't sure how effective it was because I couldn't find anything that nailed down the % of the vinegar... the posts I found on the net said its anywhere from 5-10% and I was concerned that much variation could be an issue.

As an aside, how long could I expect a 1% solution to last, both for prints and film? Would it be a new bath each time, or could it be reused once or twice?

I'm very grateful for all the advice, thank you
 
When I do use stop bath for film (usually only when using my home brew parodinal as it is very alkaline) it is single use. For paper, acetic acid stop bath has its own built olfactory indicator, when the stop bath no longer smells of vinegar swap it for new solution. Oh that all brings back memories of 50 plus years ago as 13 year old mixing up my own developers, stop baths and fixers from scratch in the attic box room / darkroom (but I did come from a family of scientists and the attic room next door was the laboratory).
 
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