Stop Bath.. How important?

[Vaughn]

Why?

1) Because stop bath for film is not critically needed for excellent results.
2) One less (potentially hazardous) chemical to have around students in a tight place.
3) Simplified the process; one less chemical to go accidentally back in the wrong bottle, one less chemical to have ready in a graduate cylinder in a small room with people all around you, etc..
4) Since no one used stop bath and all stopped with water the same way every time, results were consistent
5) With 125 students, fixer quickly was quickly exhausted, not concerned about developer carry-over (three fill of dev tank with water before fix.)

It was done for decades, starting in the 50s when the photo program started as the third photo program to be under an university art dept in the USA. I took my first class in 1977 as a non-art major, graduated in 1981 (BS in Natural Resources Mgt), volunteered in the darkroom for ten years while working seasonally for the US Forest Service, then worked as the darkroom manager/tech for 20+ years.

PS -- we had a separate room for 4x5 film development, using SS racks and tanks. We used stop in there -- one reason was that going from tank to tank, with the middle one being the stop, was more efficient/safer that trying to use running water in the dark.

PSS -- my 120 negatives from 1977 still look great (well, not neccesarily all the images )

 

[MattKing]

The critical point to take from Vaughn's contribution here is that the decision about whether or not to use stop bath is heavily influenced by the needs and characteristics of the working area, the users, and the workflow used.
The role of each of those factors may be different when making decisions about other chemicals and approaches.

 

[Rolleiflexible]

The critical point to take from Vaughn's contribution here is that the decision about whether or not to use stop bath is heavily influenced by the needs and characteristics of the working area, the users, and the workflow used.
The role of each of those factors may be different when making decisions about other chemicals and approaches.

I thought Vaughn was saying: Stop bath is not at all important unless you are tray-developing sheet film in a communal darkroom.

Maybe we can have another hundred posts discussing what we each thought Vaughn was saying. With some good fortune, we may yet goose this thread over two thousand posts.

 

[MattKing]

I thought Vaughn was saying: Stop bath is not at all important unless you are tray-developing sheet film in a communal darkroom.

Actually Vaughan referenced sheet film developed in SS racks and tanks - not tray development.
In any event, I wouldn't phrase it that way.
I would phrase it as follows: the need for stop bath depends on who is developing the film, in what environment they are working, and what workflow they are employing, rather than any particular characteristic of the stop bath itself.
So in Vaughan's example, for most of the film (presumably roll film) developed in a communal darkroom by students, where quick fixer exhaustion is expected, the nature of the users and of the working environment suggest that stop bath isn't advantageous.
However, in one particular example, where the materials and workflow are different - sheet film in SS racks and tanks - stop bath was advantageous, so it was employed.
In other words, the question turns more on what your circumstances are, rather than any particular characteristic of the stop bath itself.
So any question about the importance of stop bath should be responded to by asking where and how might you be using it.

 

[cliveh]

1) Because stop bath for film is not critically needed for excellent results.
2) One less (potentially hazardous) chemical to have around students in a tight place.
3) Simplified the process; one less chemical to go accidentally back in the wrong bottle, one less chemical to have ready in a graduate cylinder in a small room with people all around you, etc..
4) Since no one used stop bath and all stopped with water the same way every time, results were consistent
5) With 125 students, fixer quickly was quickly exhausted, not concerned about developer carry-over (three fill of dev tank with water before fix.)

It was done for decades, starting in the 50s when the photo program started as the third photo program to be under an university art dept in the USA. I took my first class in 1977 as a non-art major, graduated in 1981 (BS in Natural Resources Mgt), volunteered in the darkroom for ten years while working seasonally for the US Forest Service, then worked as the darkroom manager/tech for 20+ years.

PS -- we had a separate room for 4x5 film development, using SS racks and tanks. We used stop in there -- one reason was that going from tank to tank, with the middle one being the stop, was more efficient/safer that trying to use running water in the dark.

PSS -- my 120 negatives from 1977 still look great (well, not neccesarily all the images )

But if I understand correctly you use stop bath for 35mm film processing. Is that because of a much higher throughput?

 

[Vaughn]

The opposite -- no stop for roll film, just 4x5 film.

Man...I thought my writing was better/clearer than this.

​

 

[MattKing]

Man...I thought my writing was better/clearer than this.

It was for me

 

[cliveh]

Sorry, I missed that bit. I apologise.

 

[Vaughn]

Sorry, I missed that bit. I apologise.

No problem -- if I have to edit a document, I need to print it out -- somehow my read comprehension drops trying to read a computer screen -- an old man's habits, I suppose.I also have a bad habit of assuming people will follow the same train of thought I am on...which is nuts because I like taking the conversation onto the off-beat paths, and looking at other possibilites beside yes/no, thisway/thatway.

 

[Augustus Caesar]

I recommend using stop bath. It stops development instantly and uniformly. Why increase risks? I tried using water rinse once, and my negatives had some residue on them that I could not remove.

 

[Hassasin]

I recommend using stop bath. It stops development instantly and uniformly. Why increase risks? I tried using water rinse once, and my negatives had some residue on them that I could not remove.

If you tried to use water and had problems, you did not do it right.

Having problems while using stop bath is also not uncommon.

A cook is only good at what he does when what he does tastes good.

 

[Mal Paso]

That's it! I'm going back to Acetic Acid! No more Communist Rhetoric!

 

[Rolleiflexible]

That's it! I'm going back to Acetic Acid! No more Communist Rhetoric!

Tastes great! Less filling.

 

[SchwinnParamount]

My comments below are meant to apply only to film development. I am also not concerned with edge effects in the discussion below.

It is true that an acid stop bath stops development faster than a water stop bath. However, "faster" does not necessarily mean "more effectively" if by that term one means "better" in the sense of better quality in the resulting image. On the other hand, if by "more effectively" one means nothing more than taking less time to stop development, then yes, an acid stop bath is more effective, but as I see it the only thing that matters is if there is a difference in the quality of the image when using one type of stop bath vs. another.

I have yet to see any results from well-controlled experiments showing that the image quality is any better when using an acid stop bath than when using a neutral stop bath. I haven't even seen experimental evidence showing that developer carryover (or alkali from the film developer) into the fixer is noticeably better (by any practical consideration) when using an acid stop bath compared to using a neutral stop bath.

As to the time difference in how long it takes to stop development, if a water stop bath takes longer to stop development than an acid stop bath then all one would need to do is cut the time spent in the developer by a slight amount to compensate for the effect. How much development time would need to be cut? I don't know, but my wild guess would be something in the range of 15 to 30 seconds to achieve the same density, and it probably depends somewhat on the film/developer combination. (I would not even be surprised if the same development time would be good enough, regardless of which stop bath were used.)

The time difference is something that could be easily determined by a few experiments. However, that's not even necessary if one is determining a personal film speed. One would simply go through that whole process of determining a personal film speed (of developing for different times) using water as a stop bath in exactly the same way as one would determine personal film speed using an acid stop bath, and the preferred development time will come out in the end without ever needing to do a comparison between acid stop vs. neutral stop.

My feeling is, I want to stop development at the same time, across the entire surface area of the negative. The bigger the negative, the more important it is to stop development instantly. I began to suspect that my edge density problem was due to stop bath working its way from center to edge - which is counter to how chemical reactions are described in AA's The Negative. The edges should stop first, and then as the chemicals are absorbed by the film, finally stop the center of the film.
I decided to stay with stop bath. As long as there is even a hint of time delay between center and edge, I am not pleased.

 

[alanrockwood]

My feeling is, I want to stop development at the same time, across the entire surface area of the negative. The bigger the negative, the more important it is to stop development instantly. I began to suspect that my edge density problem was due to stop bath working its way from center to edge - which is counter to how chemical reactions are described in AA's The Negative. The edges should stop first, and then as the chemicals are absorbed by the film, finally stop the center of the film.
I decided to stay with stop bath. As long as there is even a hint of time delay between center and edge, I am not pleased.

That's a valid comment, if it is, in fact, true. However, I have seen no evidence that using an acid stop bath produces more even development across a negative than using a water stop bath, and there are some pretty good theoretical arguments why an acid stop bath would not produce more even development than using a water stop bath.

However, theory is one thing, but experimental results are what matters in the end. I would love to see several examples of good, well controlled experiments on this topic. (So far I have only found a very small number of experimental results, and so far they have come down on the side of "no difference.")

 

[skahde]

I have an on-off relationship with acid stop-bath for film since 1985. Some processes benefit from an acid fixer, others don't care about the kind of stop you are using. With standard films and factory-made developers I can't see any difference anywhere certainly not in densitometry and I stopped using acid stop-bath years ago. No regrets.

 

[Marcelo Paniagua]

Whoa talking about long lived theads

I have always (30 years) used water so no point of comparison. I guess I could try diluted vinegar as stop bath and see if I spot any difference.

 

[Don_ih]

To reiterate, it really doesn't seem to matter with film, but it's quite important to neutralize developer in paper, or you can easily get stains.

 

[Philippe-Georges]

Since I followed this thread, I 'stopped' using a 'traditional' stop bath.
I simply put some plain water, at the same temp. the developer, in the film developing tank, reverse agitate the tank once and leave it standing for about 2 min in the hope that the developing will somewhat continue in the shadow areas, and be to weak for the highlights.
But I can't see any difference in these shadows compared to before when I used a genuine stop.
I simply continue with the 2 min water bath as it doesn't demand any chemical, no preparation, and gives me the time for checking the temp of the fix again and eventually for filling the measuring beaker with the fix...

 

[koraks]

in the hope that the developing will somewhat continue in the shadow areas, and be to weak for the highlights.

That's a loooooong shot. I'm not surprised you don't see a difference.

 

[RalphLambrecht]

Water Vs. stop bath and film development

In the last couple of months, I've seen odd density variations in my Plus-X and FP4+. On the long edges of each frame is a subtle area of increased density which runs the lenght of the frame.

I develop in a steel tank with steel reels of course. For the last couple of years I've been using water as a stop bath as I was told I risk pinholes in the film when using stop bath of too strong a concentration. Rather than determining the correct concentration, I switched to water as it is 'supposedly' as effective as stop bath.

I switched back to stop bath for my most recent roll of film and the density problem also disappeared. There were no other process changes. Is it possible that a water stop bath is less effective in stopping development at the edges of the film where it is in contact with the reels?

the water stop is definately less effective than an acid stop. With a water stop,development can continue, which is sometimes wanted to develop shadows further after highlights have developed out. In your case, it's an unwanted continuation. An acid stop stops development quicker because of the sudden drop in PH, but a too high an acid concentration can cause gas bubbles in the emulsion, which appear as pinholes in the negative. As long as the acid concentration is at or below 2%, there is little risk of this to happen. IMO an acid stop is the better solution. Others prefer a simple water stop. Well controlled, either will yield good results.

 

[JerseyDoug]

... IMO an acid stop is the better solution. Others prefer a simple water stop. Well controlled, either will yield good results.

Exactly! I pour out the developer, pour in plain water at about the same temperature, agitate for 30 seconds, pour out the water, pour in the fixer and begin agitating. The elapsed time between developer and fixer is about one minute. Since I always use the same developer any carryover developing during that minute was long ago incorporated into my established developing times.

 

[cliveh]

Stop bath has a clue in the name "STOP" If you use water, it may stop development, but more gradually than an acidic stop bath. Some printers want to immediately arrest development when they think the print has reached optimum development.

 

[alanrockwood]

One thing that would enhance this discussion is if when each person posts a comment they say whether they are talking about film development or print development.

Note added in edit:

I think I might be saying more or less what Matt said in post #1279, though his comment was more complete than mine.

 

[ame01999]

The latest Film Developing Cookbook indicates that anything but the very freshest stop bath doesn't stop development much more quickly than water does. The purpose is more to conserve the efficacy of the fixer.

I generally just use distilled water, as a little bit of compensatory development is just fine, and when I'm developing with staining, acid stop bath is prohibited anyway.