Glacial Acetic Acid as a Film Fixer

technowizard12 · Aug 8, 2012

Hey all,

I just mixed up some glacial acetic acid (or, near that molarity, at least. I kind of eyeballed it) for fixing some prints. It worked for that, and I'm wondering if there are any guidelines for using it to fix film.

tkamiya · Aug 8, 2012

Are you sure about that?

Highly diluted, it can be used as a stop bath, but I've NEVER heard of acetic acid being used as a fixer, film or paper.

edibot42 · Aug 8, 2012

Why did you decide to try that? TF5 has almost no odor, and fixes prints just fine. Glacial acetic acid, on the other hand is not something I have any interest in standing around a tray of. That and I have no idea how it would work.

RichardH · Aug 8, 2012

I had a news paper years ago call me and said they had to do my B+W print real fast, that I had sent for them to run in the bride section, because it was going bad pretty fast. I checked my fix and it had gone south. Stop will not fix a print. Look at it in a few days and see if you still have anything visible.

Richard

technowizard12 · Aug 8, 2012

It's part of a set of chemicals that came with a pinhole camera kit. I'm fairly certain that it's glacial acetic acid, since it smells overwhelmingly of vinegar, and I'm not allergic to it. Plus, it burns like hell. It might have some sodium thiosulfate in it, for all I know.

At any rate, paper I fixed with it a year ago is still as badly printed as it was the day I made it.

technowizard12 · Aug 8, 2012

The confusing thing is, to try and figure out what the fixing time is, I stuck a strip of paper in there to see how long it takes to clear. It never cleared, but the paper fixed in about two minutes.

Newt_on_Swings · Aug 8, 2012

You have been thinking you have fixed prints with stop bath for over a year? That just boggles my mind... Please do some research or listen to the advice of the people that have posted before me. Get some fixer.

kevs · Aug 9, 2012

Hi technowizard12,

The previous posters are correct. Acetic acid will NOT remove unexposed and residual silver salts from film or paper. Improper fixing will cause prints and negatives to deteriorate quickly. Acetic (or citric) acid is used as a stop bath (short stop) to neutralise the developer before fixing. If you are unsure of your chemicals, throw them away and buy some new, labelled developer, stop bath and fixer, and use them as recommended by the manufacturers.

Cheers,
kevs

technowizard12 · Aug 9, 2012

My school doesn't have a darkroom, but we do have a good chem lab. I mix my own from sodium thiosulfate that we have in stock. Usually, I know what I'm doing. I'm just away from school, and had some french-labeled fixer which I found in my closet from a while back.

I don't like to think I'm as incompetent as this post made me sound.

wiltw · Aug 9, 2012

Acetic acid is the main component of vinegar (vinegar is roughly 5% acetic acid by volume). A stop bath will usually consist of about 1-2% of acetic acid and glacial acetic acid is +99%

Acetic acid stops developer, but it does NOT remove unexposed silver salts from photographic media and render them insensitive to light.

technowizard12 · Aug 9, 2012

I understand that. I probably just guessed the components of that fixer wrong. I should probably buy English language chemicals from now on.

MattKing · Aug 9, 2012

technowizard12 said:
I should probably buy English language chemicals from now on.

I know that would be good advice for me.

technowizard12 · Aug 9, 2012

It was just so cheap! And without MSDS warnings, I don't have to feel bad about using my mother's kitchen containers!

(I made sure they weren't used for food afterwards, but still)

Mr Bill · Aug 9, 2012

technowizard12 said:
The confusing thing is, to try and figure out what the fixing time is, I stuck a strip of paper in there to see how long it takes to clear. It never cleared, but the paper fixed in about two minutes.

But how do you know the paper actually fixed?

If you want to test fixing time with paper, one way is to put several marks on a strip of paper. Then, in room light, immerse it in fixer up to the first mark for some time (say 5 seconds). Then immerse to the second mark for another time interval, and so on. Finally, immerse the entire strip into DEVELOPER (not your good tray of developer, pour a bit out for this test).

Since the fixer would ideally remove all of the developable silver halide, fully fixed paper will stay white in developer. The parts that get darker were obviously not fully fixed. So you find the first part which stayed white, and figure how long it was immersed in fixer (you'll probably find this to be about 10 seconds in a commercial rapid fix).

In the case of FILM, it will actually get clear, so is not necessary to use developer to test film fixing times.

I don't like to think I'm as incompetent as this post made me sound.

Well, of course you're incompetent, everybody is when they start out! But by suffering through these experiments, you'll have learned these things the hard way, which to me means that you have learned them better.

When one of your friends, who always follows the instructions, eventually has something go wrong, you'll be able to say, "Ok, let's test it like so and see what went wrong." Your friends will say "HOW did you know to do that?" and they'll think you're a genius.

The important thing, to me, is that you have fun learning how the things work. And try to make your screw-ups when there's nothing at stake. Good luck.

Ronald Moravec · Aug 9, 2012

film or paper is not fixed and will go yellow or change in time and you will not like it. Rewet and fix, wash, dry

David Lyga · Aug 9, 2012

I want to SHOUT out my two cents (and sense) about the DANGER inherent in the glacial stuff. As far as I am concerned it should not even be sold. Even SMELLING it is DANGEROUS. Please HEED, - David Lyga

Jim Jones · Aug 9, 2012

David Lyga said:
I want to SHOUT out my two cents (and sense) about the DANGER inherent in the glacial stuff. As far as I am concerned it should not even be sold. Even SMELLING it is DANGEROUS. Please HEED, - David Lyga

Yes, indeed! It's very nasty stuff. Long ago I bought a cheap gallon of glacial acetic acid, and diluted it to about 2% for disposable stop bath. Since it had no indicator to show when it was exhausted, it was disgarded after use. Kodak Indicator Stop Bath would have been more economical, and much more pleasant to use.

bwfans · Aug 9, 2012

So you are actually not told by the label on the chemical but rather "smells" out that is glacial acetic acid. And "It might have some sodium thiosulfate in it, for all I know."

Scientifically we actually don't know for sure if it is the glacial acetic acid, or some other chemical mix.

If it works as a fixer, it probably IS NOT glacial acetic acid.

technowizard12 said:
It's part of a set of chemicals that came with a pinhole camera kit. I'm fairly certain that it's glacial acetic acid, since it smells overwhelmingly of vinegar, and I'm not allergic to it. Plus, it burns like hell. It might have some sodium thiosulfate in it, for all I know.

At any rate, paper I fixed with it a year ago is still as badly printed as it was the day I made it.

dynachrome · Aug 9, 2012

If I had to start over I would have used citric acid all along. Aceitic acid is a component of acid hardening fixers. In High School we had the chemistry teacher order the chemicals needed for making film and paper developer. While sodium thiosulfate was inexpensive enough it was just easier to buy fixer which was already made up. There were no T-MAX films then so we used mostly regular Kodak Fixer. Today, using odorless fixer and citric acid based stop bath can make developing and printing more pleasant. This is not a replacement for adequate ventilation but the old smells are not really necessary any longer.

Gerald C Koch · Aug 9, 2012

As I mentioned on another thread acetic acid has its own built-in indicator, its smell. Sodium acetate has little or no smell. So when your stop bath loses its strong vinegar odor it's exhausted. If anyone thinks that this is a strange idea ask yourself what colorblind chemists do. They use indicators that emit an odor once a certain pH is reached.

technowizard12 · Aug 9, 2012

For the record, I wear a charcoal respirator no matter what kind of fixer I'm working with. I'm deathly allergic to aluminum, so aluminum thiosulfate causes my lungs to close up.

I know it fixed, since this particular paper tends to turn purple in a matter of minutes if it isn't and is exposed to light.

Thanks for the testing advice, Bill. That's a great idea!

polyglot · Aug 10, 2012

technowizard12 said:
For the record, I wear a charcoal respirator no matter what kind of fixer I'm working with. I'm deathly allergic to aluminum, so aluminum thiosulfate causes my lungs to close up.

I know it fixed, since this particular paper tends to turn purple in a matter of minutes if it isn't and is exposed to light.

Thanks for the testing advice, Bill. That's a great idea!

There is no aluminium in fixer. It contains sodium (slow) or ammonium (rapid) thiosulphate.

You don't know it's fixed until you did a residual silver test on it. Especially when you're guessing at the chemicals you're using by smell!

nworth · Aug 10, 2012

Glacial acetic acid is not a fixer. Moreover, it is somewhat dangerous to handle and its fumes are not only obnoxious but can be very dangerous when concentrated. Small amounts of acetic acid are sometimes used to acidify fixers so that the hardening agent (usually potassium aluminum sulfate - potassium alum) will work better. The fixing chemical is almost always a thiosulfate - either sodium of ammonium.

Glacial Acetic Acid as a Film Fixer

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