Can I use the same stop bath & fixer for B&W film and paper?

dcy · Jun 2, 2025

I think I know the answer to this question, but I wanted to check:

Last time I was doing anything in the darkroom, I was experimenting with my enlarger and making prints. That was 6 months ago. I still have a bottle of stop bath and a bottle of fixer from back then. The fixer is regular Ilford rapid fixer and the stop bath is vinegar + water.

I just shot some rolls of B&W film and I want to develop them. My plan is to:

(1) Use a pH test strip to test that the stop bath is still acidic.
(2) Use a "clip test" to test that the fixer still fixes film in less than (say) 2-4 minutes.
(3) If either solution seems to have debris, I could pass them through a coffee filter.

With those precautions, is there any reason I cannot or should not use those solutions for B&W film development?

MattKing · Jun 2, 2025

Don't.
Film leaves a bit of gelatin in the solutions. And there can be some fibre left by prints, particularly fibre prints.
In addition, fairly dilute stop bath can result in mould growth, although vinegar - which is acetic acid based - is much less prone to this than so called "odourless" stop baths, which are citric acid based.

dcy · Jun 2, 2025

Thanks!

Man. I'm glad I asked.

Donald Qualls · Jun 2, 2025

Also, due to much larger area (per session, anyway) prints will tend to exhaust fixer much more than you think they will. A single 8x10 print is roughly equal to a roll of film, and a darkroom session might see you fixing a dozen or more prints.

dcy · Jun 2, 2025

MattKing said:
In addition, fairly dilute stop bath can result in mould growth, although vinegar - which is acetic acid based - is much less prone to this than so called "odourless" stop baths, which are citric acid based.

Follow up question: How about glycolic acid? I'm going to switch to the Arista premium odorless stop bath and that's what they use.

Paul Howell · Jun 2, 2025

Ive used Artista branded fixer and stop bath without issue. I do agree that it is best practice to separate film chemistry from paper chemistry, But in a pinch if you do use one set for both be sure and test the fixer with hypo check, and after printing filter the fix.

MattKing · Jun 2, 2025

dcy said:
Follow up question: How about glycolic acid? I'm going to switch to the Arista premium odorless stop bath and that's what they use.

I've no idea.
Personally, I use acetic acid based indicator stop bath for film, and Ilfostop - which is citric acid based - for prints.
And except when I'm going to be pausing for just a few hours, I discard after every session. If I'm pausing for a short time, the working strength stop goes into a bottle for temporary storage.
You can use powdered citric acid instead for the prints - you just lose the benefit of the indicator. If you do that, pay close attention to how it feels on the fingers. It becomes a bit slippery when exhausted.
You-Brew beer and wine places are a good source for citric acid.

dcy · Jun 2, 2025

MattKing said:
Personally, I use acetic acid based indicator stop bath for film, and Ilfostop - which is citric acid based - for prints.
And except when I'm going to be pausing for just a few hours, I discard after every session. If I'm pausing for a short time, the working strength stop goes into a bottle for temporary storage.
You can use powdered citric acid instead for the prints - you just lose the benefit of the indicator. If you do that, pay close attention to how it feels on the fingers. It becomes a bit slippery when exhausted.
You-Brew beer and wine places are a good source for citric acid.

Oh, I have citric acid at home. I can't remember what I was planning to do with it. Happy to use it for prints.

Any reason why citric acid would be better for prints?

EDIT: I guess that a cheap stop bath that goes moldy when stored is an fantastic choice if you plan to make 1L and then toss it at the end of the day.

MattKing · Jun 2, 2025

dcy said:
Oh, I have citric acid at home. I can't remember what I was planning to do with it. Happy to use it for prints.

Any reason why citric acid would be better for prints?

Citric acid doesn't smell nearly as bad as acetic acid - that is what why citric acid is used in most "odourless" stop baths.
Stop bath relying on citric acid is probably more expensive to make and sell if you are doing so commercially - you can't make as strong a concentrate - and working strength citric acid based stop bath keeps less well than working strength acetic acid based stop bath, so high volume users may not prefer it.

F4U · Jun 2, 2025

I've always used Dektol, Kodak Indicator stop bath and Kodak fixer. Never cared one bit about the smell. It's what a darkroom is SUPPOSED to smell like. And the fixer and stop bath is good for film and paper. And all of it keeps for years.

brian steinberger · Jun 2, 2025

F4U said:
I've always used Dektol, Kodak Indicator stop bath and Kodak fixer. Never cared one bit about the smell. It's what a darkroom is SUPPOSED to smell like. And the fixer and stop bath is good for film and paper. And all of it keeps for years.

Not sure I would keep working solutions of either stop bath or fixer for years. Concentrate possibly.

Pieter12 · Jun 2, 2025

I don't use stop bath with film, just plain water.

MattKing · Jun 2, 2025

Pieter12 said:
I don't use stop bath with film, just plain water.

And we have pages and pages and pages of discussion about this, in one of the longest threads on Photrio.
Both approaches have their fans.

pentaxuser · Jun 2, 2025

F4U said:
And the fixer and stop bath is good for film and paper. And all of it keeps for years.

So you use the same fixer and stop bath for both with no ill effects which seems to be against all the advice I have ever seen on Photrio

Can I ask how you work out the life of a fixer that has fixed both films and paper?

Thanks

pentaxuser

GregY · Jun 2, 2025

pentaxuser said:
So you use the same fixer and stop bath for both with no ill effects which seems to be against all the advice I have ever seen on Photrio

Can I ask how you work out the life of a fixer that has fixed both films and paper?

Thanks

pentaxuser

P, I read that as he simply used those products..... not that he re-used those products

F4U · Jun 2, 2025

GregY said:
P, I read that as he simply used those products..... not that he re-used those products

No I pour them back in the bottle. Stop bath will start changing from the yellow to a more brown color when it's getting weak. And fixer will start turning yellowish. Often times fixer may start to take on a "stinky" smell and have silver particles and/or a sludge that comes up from the bottom when you tip the jug. I would say that fixer is most likely to be thrown out before the "recommend limit' is even reached. There used to be an Edwal hypo chek where you drop in a drop and if the fixer is exhausted, that drop will turn to a cloud. Plus 60 years of doing this and you kinda know just from the various clues. Besides, if you are really serious about your film and prints you'd be using a second fresh bath that you'd rotate into first bath and make a new second bath. Plain old Kodak Fixer is the best thing there is.

reddesert · Jun 2, 2025

I think I used to use the same indicator stop bath for film and paper. I would pour the working solution back into a 1-liter bottle. I always kept track of how many films or papers had been in my stop and fixer by marking tickmarks on a label on the bottle. Many fixers have different dilutions for film and paper, and for that and other good reasons mentioned above, I used separate working solutions of film fixer and paper fixer.

Stop bath is very cheap and I would rarely actually get to the end of a small bottle of stock-strength Kodak indicator stop bath before I'd move or something. Vinegar + water is presumably even cheaper. So there is no particular need to double-use it for film and paper, I was just saving space.

IMO, the most costly (and most critical) chemical is your developer - you can re-fix a film or paper, but you can't re-develop it. I would typically use working strength developer as one-shot (for film) or one-session (for paper). After that, stop and fixer are relatively inexpensive, and easy to keep track of how much capacity you've used.

It's possible to make this as hard as possible on yourself as a relative beginner by home-brewing ingredients or overusing chemicals or trying to optimize different developer choices and methods. Or you can just use fairly standard chemicals and development methods (standard timing, agitation, etc) and try to focus your attention on the other parts of the process. You will have occasional screwups, everyone does, so it is worth trying to minimize the number of things that can go wrong.

GregY · Jun 2, 2025

F4U said:
No I pour them back in the bottle. Stop bath will start changing from the yellow to a more brown color when it's getting weak. And fixer will start turning yellowish. Often times fixer may start to take on a "stinky" smell and have silver particles and/or a sludge that comes up from the bottom when you tip the jug. I would say that fixer is most likely to be thrown out before the "recommend limit' is even reached. There used to be an Edwal hypo chek where you drop in a drop and if the fixer is exhausted, that drop will turn to a cloud. Plus 60 years of doing this and you kinda know just from the various clues. Besides, if you are really serious about your film and prints you'd be using a second fresh bath that you'd rotate into first bath and make a new second bath. Plain old Kodak Fixer is the best thing there is.

My apologies....although as far as "Plain old Kodak Fixer is the best thing there is" ....Unlike film, film developer & paper developer, I'm an equal opportunity user where fixer is concerned....Kodak, Ilford Hypam, Formulary T4 or T5, ....i've even got a five pound pail of sodium thiosulfate....& haven't seen any difference in results

F4U · Jun 2, 2025

I'm a "mix my own' guy too. Just so happens i have a half dozen full bottles of Kodak indicator stop bath and I'm 68. so I suppose it's safe to say it's more than a lifetime supply. And I'll use any hypo or fixer I can get my hands on. If it's not Kodak Fixer, I "doctor" it to be the same thing. I like my acid hardening fixer. I've used commercial pre-mixed rapid fixers, but sooner or later they precipitate sulfur and start stinking to high heaven. I'm not an "eco chemical' kind of guy, ad am not bothered by the acetic acid darkroom smell. 'The smell of napalm in the morning". or something like that.

MattKing · Jun 2, 2025

As Kodak Indicator stop concentrate is pretty close to glacial acetic acid plus indicator, I hope those bottles are either the really old glass ones or are stored in a bucket or other outer container, because the more modern plastic bottles can usually only be expected to survive a decade or so before they start to deteriorate and leak.
And you really don't want glacial acetic acid leaking anywhere!

GregY · Jun 3, 2025

F4U said:
I'm a "mix my own' guy too. Just so happens i have a half dozen full bottles of Kodak indicator stop bath and I'm 68. so I suppose it's safe to say it's more than a lifetime supply. And I'll use any hypo or fixer I can get my hands on. If it's not Kodak Fixer, I "doctor" it to be the same thing. I like my acid hardening fixer. I've used commercial pre-mixed rapid fixers, but sooner or later they precipitate sulfur and start stinking to high heaven. I'm not an "eco chemical' kind of guy, ad am not bothered by the acetic acid darkroom smell. 'The smell of napalm in the morning". or something like that.

Old stuff. Tell me about it. I just finished off a gallon of glacial acetic acid, I bought when my kids were in grade school.....(They've past 30 now).....

F4U · Jun 3, 2025

Thanks. I'll find some glass bottles and transfer them. Outdoors. That is some mean stuff. Ever put a bottle of glacial acetic acid or Indicator Stop Bath up to your nose and taken a whiff? You won't do THAT again.

MattKing · Jun 3, 2025

F4U said:
Thanks. I'll find some glass bottles and transfer them. Outdoors. That is some mean stuff. Ever put a bottle of glacial acetic acid or Indicator Stop Bath up to your nose and taken a whiff? You won't do THAT again.

If you spill a drop, the Kodak Indicator Stop bath concentrate will take the colour out of a laminate counter top.
Don't ask me how I know ......

Donald Qualls · Jun 3, 2025

MattKing said:
Kodak Indicator Stop bath concentrate will take the colour out of a laminate counter top.

Well, it is about 80% strength acetic acid. It'd probably do the same for a pair of jeans.

koraks · Jun 3, 2025

Donald Qualls said:
It'd probably do the same for a pair of jeans.

Not to mention the skin underneath the jeans.

Can I use the same stop bath & fixer for B&W film and paper?

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