Stop Bath.. How important?

[alanrockwood]

Well, one thing observed is that if a water rinse is like the second bath of a 2 bath developer, it is then not useful to reuse it. It should either be dumped right away or be one consisting of running water.

As for Metol not being mentioned, that is where I come in. Note my comments above about PPD being retained in color processes. A process with a stop or an acid stabilizer extracts the PPD from the coupler droplets. I have the advantage of having talked to Grant about this and other problems and know that Metol is very hard to remove from coatings without an acidic extraction of some method. I mentioned all of this before.

Remember that this work of Grant's was done while he worked at EK and was heavily redacted. There were internal reports on this subject, but he had to go to an external report and use that report and rely on others to generalize what might happen if you did not have an all alkaline process.

This is a very difficult subject with many different views having been expressed. I have used both, when there was no acid present to make stop or some such. But, mostly I use a stop.

As for non uniformity, it goes up with format size and with paper vs film. Remember that this work was done in the age of fiber based paper supports and thicker film coatings.

The attached images are not properly identified. The first image is from Anchell and Troop. Sorry Steve, sorry Bill.

PE

As you say, it makes sense to discard a water stop bath and not reuse it. My processor (Phototherm) discards the water stop bath with each use.

It's too bad the internal Kodak documents aren't publicly available. My guess is that they have disappeared over the years, particularly after the bankruptcy if not before. As an analogy to this, I once asked a technical question to Ilford related to variable contrast filters, and they no longer had the relevant technical information needed to answer the question.

Regarding the difficulty of metol extraction, does the difficulty arise from precipitation of metol under certain conditions? One of your posts hints at this. Alternatively, it could be that metol has a high affinity for gelatin or paper or film base and is hard to remove because of that.

Regarding the Haist volumes, as I spot read in different sections I see the book is extremely informative.

Regarding unevenness of development, your comment that the problem is worse for larger sizes is consistent with a theory that unevenness is largely the result of the difficulty of exposing the full sheet of developed film or paper to stop bath at the same instant. This would in turn tend to favor using a less active developer and longer development time, so the variations in application of stop bath would be less important.

 

[Photo Engineer]

Metol is not very soluble in alkali and also only slightly soluble in water at room temp. That is why it is sold as the Sulfate salt. This has been mentioned before here on Photrio before. Acid helps extract it. It behaves much like a PPD.

Kodak has a 20 year document retention program. All documents are destroyed after 20 years.

Not everyone has the sense to discard a water stop after every use. I have seen some use one all afternoon in a printing session and complain late in the day about their results.

Haist's book is indeed superb, and having read the unredacted version of several of the chapters, it would have been the photo bombshell report of its day. Unfortunately, we the editors had our orders.........

Enjoy reading it. I have not only read it several times, I get dizzy (somewhat) when I have to accurately refresh my memory by rereading it once again.

Unevenness is particularly evident in prints.

PE

 

[Ian Grant]

Thank you Ron for posting Haist's comments which talk about the need for a water rinse or acidic stop-bath which is also the recommendation of all the film manufacturers.

What's most important is Haist actually calls the water rinse of 30-60 seconds "a water stop-bath". That should be enough to end any dispute that a water rinse is not sufficient in the near 14 year life of threads on this topic

Ian

 

[Photo Engineer]

I hope you saw the comment by St. Ansel in my earlier post from A&T.

I have quotes from Jacobsen, Jacobsen and Jacobsen, Mason and Eaton as well. All of these agree that washing after development can be used, but they prefer a stop. And the wash, if used, must be running water or must be changed frequently.

I have found that a stop bath always works, but a rinse does - until it doesn't for one reason or another. And then you have lost work and spend a lot of time trying to figure out what went wrong.

PE

 

[Ian Grant]

I have found that a stop bath always works, but a rinse does - until it doesn't for one reason or another. And then you have lost work and spend a lot of time trying to figure out what went wrong.

PE

Well I've been developing films and making darkroom prints for over 50 years, not quite as long as you though

I always use an acid stop-bath when printing, and as I use mostly FB papers that makes it more important, However I stopped using a stop bath for film processing in 2006, I've never had a single issue as I'm using a slightly acidic fixer, either Hypam, Ilford Rapid Fixer all roughly pH 5.4, or Hypam. If I used an alkali or near neutral fixer I would use an acid stop-bath.

Ian

 

[alanrockwood]

Just for sake of discussion, let me throw in the idea of using an alkaline stop bath. Yes, I know this idea is going to grate on many people's nerves (break out the pitchforks and torches), but please hear me out.

If the stop bath is pH-matched to the developer then any consideration related to precipitation of the developer compounds (metol, hydroquinone, etc.) via pH changes become moot, and the the developer would then be depleted through a combination of diffusion out of the film and depletion via reaction of the developer with the silver halide in the film.

This scheme would act in a fashion somewhat between that of a conventional developer and Diafine, but probably more like a conventional developer.

If one is worried about carryover of the alkaline solution into the fixing bath then a water wash in between the stop bath and the fixing step could take care of that issue. This would also deal with any issue with respect to pH shock when transferring the film between solutions.

I suppose it could be a bit of a stretch to call an alkaline stop bath a true "stop" bath when compared to an acid stop bath. However, it would serve the two functions of a conventional stop bath, i.e. terminating development (albeit more slowly) and preventing carryover of developer into the fixing bath. If it is an alkaline fixer then the additional wash step would be unnecessary.

Whether this would be desirable or not from a practical standpoint could be debated, but it would no doubt work, though it might require slightly shortening the nominal development time. Even if not a practical scheme it might be interesting from an experimental point of view to try to sort out some of the issues discussed here.

 

[Photo Engineer]

Actually Alan, an alkaline stop is not impossible. I formulated one about 20 years or so ago. It worked quite well, but the ingredients were not very conducive to good fixing. It exhausted the fix at about 2 - 5x the normal rate. There are several formulas possible, but all of them have one problem or another. And they can be considered true stop baths because they stop development, although I find that the stop action is very slow and required high agitation.

PE

 

[Deleted member 88956]

685 posts and counting on importance of stop bath, with multiple entries confirming it makes no difference in final results. There is ... in theory, and once theory is involved here is no stopping to the discussion. Shouldn't one be more worried about the whole process and eradicate what does make a difference instead?

 

[Bronson Dugnutt]

From my limited experience, the only time a stop bath has been absolutely required is before using using a separate bleach & fix when developing C-41. Even a thorough wash prior to bleaching leads to a profound color cast at the end of the process; film comes out of the tank with a green cast, rather than the expected orange.

I can't speak to the archival impact.

 

[Skeeterfx20]

A very long read that's for sure. I don't know if stop bath is needed or not in relation to developing black and white negatives. I never experimented not using it or trying something different. What I do know it works. Maybe everything would work just fine without it. What I certainly know is I love the smell of stop bath in the darkroom. That's enough for me to keep using it.

 

[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 stop bath is the way to go even that is true that pinholes may develop in a too-acidy environment.Just avoid that by sticking to the manufacturer's instructions.

 

[Photo Engineer]

Pinholes will not take place with modern films. It was only observed in certain deep tank automated processes and became "fake news" due to over reporting.

PE

 

[RalphLambrecht]

Pinholes will not take place with modern films. It was only observed in certain deep tank automated processes and became "fake news" due to over reporting.

PE

good to know.one more reason to use a stop bath.

 

[Ian Grant]

Pinholes will not take place with modern films. It was only observed in certain deep tank automated processes and became "fake news" due to over reporting.

PE

That should be with most modern films. some films have softer emulsions than others Fuji Acros, and all Fomapan films have softer emulsions with the wrong circumstances pinholes or reticulation can occur.

Ian

 

[Photo Engineer]

If you read the seminal book by George Eaton, he explains that pinholes only took place in soft films in deep tank commercial processors where the film was under pressure due to the depth and then rose quickly to the surface due to the motion in the tank.

ALSO, the developer had to use Carbonate because CO2 was the source of the pinholes.

PE

 

[Ian Grant]

If you read the seminal book by George Eaton, he explains that pinholes only took place in soft films in deep tank commercial processors where the film was under pressure due to the depth and then rose quickly to the surface due to the motion in the tank.

ALSO, the developer had to use Carbonate because CO2 was the source of the pinholes.

PE

What Eaton wrote years ago is irrelevant as people have still encountered pinholes and with other types of processing, in addition some developers use Carbonate. Blanket statements aren't valid when pinhole issues are still seen,

Ian

 

[Photo Engineer]

So far, in every case we have seen pinholes, they turned out to be with the 3rd tier films. Most of these have now vanished.

As for most REPORTS of pinholes, they are usually air bubbles or other types of defects.

 

[Ian Grant]

So you are saying Kodak is a 3rd tier film manufacturer, because there's enough reports of pinholes in Tmax 400, also Fuji Acros does that make Fuji a 3r tier manufacturer ?

Ian

 

[Photo Engineer]

I have not seen a reported instance of either film with pinholes that could not be shown to be air bubbles or something else.

PE

 

[lonelyboy]

Do you use a stop bath in B/W processing? I did a test using stop bath vs tap water wash. Here is the comparison result:

Stop Bath? or Not? – H. M. Lai's Film Blog

 

[foc]

I have never used a stop in all my years processing B&W films both personally and professionally.
BUT then I never use a pre wash.
BUT I do use a squeegee.
So maybe I am not the one you should ask.

 

[Deleted member 88956]

We went over this to lengths, horse died several times in that thread. But you might want to look it up as there was some good input, not just how to dispose a dead horse

 

[DeletedAcct1]

Do you use a stop bath in B/W processing?

Yes

 

[Deleted member 88956]

Do you use a stop bath in B/W processing? I did a test using stop bath vs tap water wash. Here is the comparison result:

Stop Bath? or Not? – H. M. Lai's Film Blog

No, never have, never had a problem either.

This is how it is going to proceed, a yes and no, or not always at times. Might want to put up a poll to tally answers up, somebody might win it.

 

[Anon Ymous]

Yes, always used and will continue to do so. I find it easier than doing several water changes. Never had any problems, not even when using carbonate developers, but I've only used well hardened films. Water changes can work, but in case of very short development times, it's not a great idea. For instance, in C41 it's definitely not a good idea. It's also not a good idea when printing, it can theoretically work, but quickly becomes impractical.