Using Vinegar as a Stop Bath

[darkroommike]

If you are blessed to still have a local camera store use indicator stop bath (don't really care which brand) or have them order 28% acetic acid. If you can find a local source for glacial acetic acid that also works well, just dilute it to 28% using the old 3+8 ratio and add the acid to water not water to acid. You could also check Ebay, there's an outfit that sells glacial acetic for bio-diesel conversions of cooking oil that has it pretty cheap. Worst case? Use either vinegar or citric acid. Citric acid available in tiny expensive bottles as "sour salt" or in much cheaper bags weighing up to 25 Kg or 50 lbs.

 

[MattKing]

You-brew stores may have citric acid is practical quantities.

 

[LAG]

If you do the math, you will find that the stop bath is usually cheaper to use than vinegar.

It depends on the volume of the stop baths you do, and it depends on the volume of salads you eat

And as for the stop bath vs. water debate:
1) be prepared for religious fervor;

I agree

2) running water is necessary for paper, and highly advantageous for film;
3) films and papers and fixers were designed with stop bath in the process;

I do not

... I guess if plain water is acceptable then any reasonable dilution of vinegar is as well.

Well, it is not that simple equation, both (plain water and vinegar) need a more extensive reasoning

... use it for your salad or fries...

... or avocado

I'm not sure I'd develop a taste for that.

As for using vinegar or or stuff sold as photographic stop bath, acetic acid is acetic acid whether it comes from Freestyle or the local grocery store ....

Well, it is not that simple equation either. You don't use Ilfostop with your salads, do you? Both can be acetic acid but they are not the same at all.

My 16 ounce bottle of Kodak indicator stop bath makes 8 US gallons of working strength indicator stop bath at the manufacturer's recommended dilution. With film, I usually use it half strength (one shot), so that means 16 US gallons of working strength stop bath.
I don't know how much shelf space you have, but I do know that I don't have enough to store the necessary equivalent amount of vinegar.
In my case and market, stop bath is cheaper than vinegar.

Again another decompensated equation, nobody needs that amount of vinegar at home, generally speaking 0,26 gallons of vinegar is more than enough for your - once in a while - darkroom use and your - once in a while - salads at the same time with the same bottle, try to do the maths with the Kodak Indicator to other way around. If you (or your wife *) like salads you have to buy vinegar as well.

As you can see other's milages may vary!

(*) by the way, how is she? Has she recovered her foot from the race?

All the best!

 

[Scott Murphy]

I'm confused why someone looking to use something other than traditional stop bath, for whatever reason, wouldn't just use plain water?

Plain water simply removes most of the last developer from the tank, it does essentially nothing chemically. Water has a neutral, or nearly so, pH. Vinegar, or Stop Bath, both of which contain acetic acid, neutralize the alkaline action of the developer. This is why it is called STOP bath. Rudimentary acid-base chemistry.

 

[MattiS]

I use acetic acid (60%), diluted to 3%, 1+19. That‘s how I learned it in a darkroom class some years ago.

 

[Colin Corneau]

 

[cowanw]

Plain water simply removes most of the last developer from the tank, it does essentially nothing chemically. Water has a neutral, or nearly so, pH. Vinegar, or Stop Bath, both of which contain acetic acid, neutralize the alkaline action of the developer. This is why it is called STOP bath. Rudimentary acid-base chemistry.

While water is categorized as neutral, That does not mean that it does nothing. It is 1000 times more acidic than my developer. I use a one litre system so supposing I pour out most of my developer up to say 20 cc's and add 1000 cc's of water, Ph will fall from 10 to a Ph of 8ish. My developer ceases to work at Ph's of 9ish.
Repeating this once, will bring the Ph down to 7.
Diffusion into the paper is another concern, although we are lead to believe that developer rapidly depletes on the surface of paper if we do not agitate full working strength developer of working Ph.
As long as one is consistent, differences in times/ concentrations between us is cancelled as testing/experience gets to the negative the single person wants. Which is why there are many ways to develope the cat. Somehow they all work.

 

[138S]

If you are blessed to still have a local camera store use indicator stop bath (don't really care which brand) or have them order 28% acetic acid. If you can find a local source for glacial acetic acid that also works well, just dilute it to 28% using the old 3+8 ratio and add the acid to water not water to acid. You could also check Ebay, there's an outfit that sells glacial acetic for bio-diesel conversions of cooking oil that has it pretty cheap. Worst case? Use either vinegar or citric acid. Citric acid available in tiny expensive bottles as "sour salt" or in much cheaper bags weighing up to 25 Kg or 50 lbs.

Glacial acetic is a hazard, better mixing it outdoors.

If you calibrate your film you will see that a plain water stop bath delivers the same result. With plain water developement needs a few seconds more to totally stop, so you may shorten development some 5 to 10 seconds for a perfect match.

Generally plain water is better because you don't carry chem to the fixer (that can be alkaline!), you dump the water every time so it does not accumulate developer like a reused stop bath.

 

[MattiS]

Thanks - helps me a lot.

 

[RalphLambrecht]

For those who have garnered consistent results from using vinegar in film/print processing, what type (cider, distilled white, etc.) is recommended, and should it be diluted or not?

Yes, White vinegar diluted to 2% works fine! For films and prints!

 

[darkroommike]

Glacial acetic is a hazard, better mixing it outdoors.

If you calibrate your film you will see that a plain water stop bath delivers the same result. With plain water developement needs a few seconds more to totally stop, so you may shorten development some 5 to 10 seconds for a perfect match.

Generally plain water is better because you don't carry chem to the fixer (that can be alkaline!), you dump the water every time so it does not accumulate developer like a reused stop bath.

• Glacial acetic acid is only hazardous to folks that do not have experience in handling chemicals. Taking it outdoors is only a good idea if you have a source of running water near by just in case of a spill or splash.
• I don't use an acid stop bath for film processing but I would if I were running a continuous processor like a cine, roller transport, or one of those HUGE Refrema type dip and dunks.

 

[Doremus Scudder]

Distilled vinegar is just an acetic acid solution. It works fine if you dilute it correctly. Stop baths are typically in the 2-3% range. You do the math for the product you have.

Don't use other vinegars unless you really want to play with non-traditional toning (maybe a red-wine vinegar tinged print, or balsamico-brown?)

A water stop bath will do the job, but comes with some inherent shortcomings. Running water is best. If you just use a tray of water, it needs to be changed often or developer will build up in you stop bath, changing it to a go bath...

A stop bath, water, or otherwise, does not remove developer from the film/paper. It stops it action by changing the pH of the environment so it is no longer active. Developer transferred from a water stop to an alkaline fixer can more easily be re-activated causing streaking and fogging if one turns on the white light too soon. (don't ask how I know...). the same can happen with an acid stop, but is less likely. It's a good idea to fix film for at least half the total fixing time before exposing it to white light.

Most alkaline fixers are formulated with enough buffering to allow the use of an acid stop bath without it adversely affecting the pH of the fixer. The late Ron Mowrey (PE) confirmed this in a post some years ago about TF-5.

If using an acid or more neutral fixer (e.g., Ilford Rapid Fixer), using an acid stop will prolong the life of the fixer, and is therefore recommended.

Citric acid works well as a stop bath. It is available as a pre-mixed photo chemical (e.g., Ilfostop) or as a raw chemical in powder form.

Concentrated acetic acid is/was available as a photochemical too. Glacial acetic acid is nasty stuff and needs to be handled with care. Its fumes are more than irritating, so ventilation is important. 28% acetic acid is less aggressive and easier to deal with; just dilute 16ml/liter. Kodak Indicator Stop concentrate is 20% acetic acid with the addition of an indicator dye IIRC.

Best,

Doremus

 

[Adrian Bacon]

If you do the math, you will find that the stop bath is usually cheaper to use than vinegar. Vinegar is easier to find on a shelf nearby, but takes a lot more storage space than highly concentrated stop bath.
And as for the stop bath vs. water debate:
1) be prepared for religious fervor;
2) running water is necessary for paper, and highly advantageous for film;
3) films and papers and fixers were designed with stop bath in the process;
4) fixer lasts longer with stop bath, and fixer is more expensive to use than stop bath and more complex to handle when you are discarding it than stop bath.

religious fervor indeed.

the point of a stop bath is to quickly lower the ph to stop development. Secondarily, depending on the process in use, it may also help maintain the ph of subsequent baths. How you get there matters less, and your situation should dictate what you use.

in my case, since I do BW film, BW prints, C-41 film, and E-6 film, it’s simpler and easier to just have one universal stop bath made up of distilled white vinegar diluted, typically 4 parts water to 1 part vinegar. If I were a black and white only shop, then I’d use the stop bath supplied by the manufacturer.

 

[138S]

• Glacial acetic acid is only hazardous to folks that do not have experience in handling chemicals. Taking it outdoors is only a good idea if you have a source of running water near by just in case of a spill or splash.
• I don't use an acid stop bath for film processing but I would if I were running a continuous processor like a cine, roller transport, or one of those HUGE Refrema type dip and dunks.

Not only glacial is a hazard, citing The Darkroom Cookbook:

"The fumes which emanate from acetic acid stop baths are perhaps the single greatest health hazard in the darkroom. Over time, these fumes can cause damage to the delicate membrane of the sinuses, resulting in respiratory problems."

I use acetic acid stop bath for paper, but I try to have a good ventilation, perhaps I'll use citric in the future.

the point of a stop bath is to quickly lower the ph to stop development.

Adrian, let me partially disagree.

IMO "quickly" is not important, if a water bath effectivelly develops 10 seconds more than acid stop bath you simple shorten 10 seconds developement for the same effect.

IMO, in the past the "principal point" was to not damage an acid stop bath with the alkaline developer carried with film or paper. Today we also use alkaline fixers so if we carry acid stop bath to the fixer this is a problem, and we may have to correct fixer's pH...

It always has been called "stop bath", but real effect was protecting fixer in the times in what fixers were mostly acid. Amazingly a water stop bath also protects fixer, we may make several fast rinses with plain water so the film put in the fixer will be clean.

 

[Dennis S]

For the last few yrs I have given up acid stop for film and just use water and then TF-5. I see visually with a scan that there was really no difference. I believe that TF fixers were formulated to use no acid stop so just following instructions.

 

[CMoore]

It seems like Opinions/Trends change from time to time.
When i asked a few years ago (regarding a do it yourself method) , what seemed to be popular was just water for my 35mm film and Citric Acid for my Stop-Bath for paper.
I have not strayed from that routine for the last 4-5 years.
Citric Acid is so cheap and so easy, i might even change it 2 times in one day if i am Printing/Testing a lot.

 

[Sirius Glass]

I use stop bath with indicator. It is one of the least expensive photo processing chemicals available to us. If you cannot afford stopbath with indicator, perhaps you should take up knitting, quilting or crocheting.

 

[138S]

I use stop bath with indicator. It is one of the least expensive photo processing chemicals available to us. If you cannot afford stopbath with indicator, perhaps you should take up knitting, quilting or crocheting.

Let me point that's not about cost, it's about convenience and performance.

Convenience because you don't have to mix and keep concentrate and diluted bottles, you use tap water that you dump every time.

Performance because you don't carry chem to the fixer. If using an acid bath you carry acid to the fixer (that can be alkaline) and some developer the stop bath accumulates over time, instead with water bath you always use new fresh water, not accumulating other chem, fixer takes just wet and clean film and no other contamination.

Anyway there is nothing wrong in using acid stop... For paper I use acid stop bath, for film I use water. YMMV, of course.

For the last few yrs I have given up acid stop for film and just use water and then TF-5. I see visually with a scan that there was really no difference. I believe that TF fixers were formulated to use no acid stop so just following instructions

In general, I guess no fixer requires acid stop bath, plain water works for all, with a good rinse. TF-5 is mildly acidic: https://www.photrio.com/forum/threads/alkaline-stop-bath-tf5-fix.79328/#post-1086073

 

[darkroommike]

Glacial acetic acid may indeed be harmful to the soft tissues in your respiratory system, as is the ammonia in alkaline fixers and selenium toners, and the hydrogen sulfide in other toners, H2S is toxic not just irritating. The stop bath in my tray is a 2% solution. If you have that sort of sensitivity no one can help.

 

[RalphLambrecht]

Not only glacial is a hazard, citing The Darkroom Cookbook:

"The fumes which emanate from acetic acid stop baths are perhaps the single greatest health hazard in the darkroom. Over time, these fumes can cause damage to the delicate membrane of the sinuses, resulting in respiratory problems."

I use acetic acid stop bath for paper, but I try to have a good ventilation, perhaps I'll use citric in the future.



Adrian, let me partially disagree.

IMO "quickly" is not important, if a water bath effectivelly develops 10 seconds more than acid stop bath you simple shorten 10 seconds developement for the same effect.

IMO, in the past the "principal point" was to not damage an acid stop bath with the alkaline developer carried with film or paper. Today we also use alkaline fixers so if we carry acid stop bath to the fixer this is a problem, and we may have to correct fixer's pH...

It always has been called "stop bath", but real effect was protecting fixer in the times in what fixers were mostly acid. Amazingly a water stop bath also protects fixer, we may make several fast rinses with plain water so the film put in the fixer will be clean.

Citric stop bath is safe and works just fine.

 

[138S]

Citric stop bath is safe and works just fine.

Yes... I guess it's the right solution.

With paper test strips one wants to open lights ASAP to judge, with paper in the fixer... Specially if fixer alkaline I guess paper tends to start development again, in that situation an acid stop bath should be better, and citric is good advice...

 

[guangong]

Amazing. Folks think nothing of spending a couple grand on equipment, but quibble about how many pennies are saved using various alternative to plain old acetic acid as fixer. My liter of glacial acetic acid will probably become a part of my estate.
Sort of the same pattern as those threads about owners of expensive late model Leicas who try to find the cheapest film.

 

[Colin Corneau]

Thanks - helps me a lot.

Sorry to hurt your feelings and create a shame spiral, but this has just been gone over so, so many times.

Same answers each time - don't do it. Cheap out on something else, not your materials...simple as that.

 

[darkroommike]

Amazing. Folks think nothing of spending a couple grand on equipment, but quibble about how many pennies are saved using various alternative to plain old acetic acid as fixer. My liter of glacial acetic acid will probably become a part of my estate.
Sort of the same pattern as those threads about owners of expensive late model Leicas who try to find the cheapest film.

• Acetic acid is not fixer but is only a stop bath.
• At one point I did the math, because I am that cheap. A tray of 2% acetic acid stop bath, regardless of the source, is about the same price, whether you use household 5% vinegar, 28%, or glacial.
• Citric acid in all it's forms is more per tray with less capacity per liter of working solution. And you can't (or shouldn't) save a tray of diluted citric acid stop (even if using a commercial preparation with an indicator) because stuff grows in it.

 

[tezzasmall]

I've read of people using Citric Acid in their Nova slot processors as a stop bath, as well as occasionally in trays, but then a mould appears, mostly in the former.

Is there any preservative that can be added to the stop bath, to stop the above happening, and thus avoid having to constantly drain and refill a Nova, which are bought to partly avoid this?

Terry S