Stop Bath.. How important?

alanrockwood · Jan 26, 2021

michael_r said:
Bad idea, Vaughn. Remember that a water stop bath works relatively slowly by simply diluting/washing the developer out, not chemically stopping the developer. Development does not stop immediately. So if the lights are on, exposing the film or paper, while development is slowing down but still happening...

Probably a very negligible effect though.

alanrockwood · Jan 26, 2021

Is it just me, or has anyone else noticed that no one on this thread has produced even one example of documented experimental evidence that stop bath vs. water makes even one scintilla of difference in film processing? For paper processing this may be a bit more of an open question, but I don't think anyone anyone has demonstrated a difference there either.

To me it's kind of like putting on the breaks when approaching a stop sign. You can either put the brakes on a little early and slow down gradually (like a water stop), or slam on the breaks at the last instant and slow down real fast (like an acid stop). Either way you end up in the same place and in the same final state.

MattKing · Jan 26, 2021

alanrockwood said:
Is it just me, or has anyone else noticed that no one on this thread has produced even one example of documented experimental evidence that stop bath vs. water makes even one scintilla of difference in film processing?

I'm sure that the "documentation" would relate to commercial processing throughput and fixer efficiency and longevity.
With a side of development precision, of course.

Lachlan Young · Jan 26, 2021

MattKing said:
I'm sure that the "documentation" would relate to commercial processing throughput and fixer efficiency and longevity.
With a side of development precision, of course.

I think the documentation and analysis probably went far deeper into investigating methods (and available time before streaks appeared) for causing rapid cessation of development - especially in multilayer coatings - at a far greater level than people like to think. And it was probably all highly confidential, given its relevance to colour process techniques/ technology.

And I bet work was done to investigate the effects of using the wrong procedure (water rinse) on development. After all, how do you think the effects of the water rinse after the FD that are exploited in the E-6 process were discovered?

Sirius Glass · Jan 26, 2021

alanrockwood said:
Is it just me, or has anyone else noticed that no one on this thread has produced even one example of documented experimental evidence that stop bath vs. water makes even one scintilla of difference in film processing? For paper processing this may be a bit more of an open question, but I don't think anyone anyone has demonstrated a difference there either.

To me it's kind of like putting on the breaks when approaching a stop sign. You can either put the brakes on a little early and slow down gradually (like a water stop), or slam on the breaks at the last instant and slow down real fast (like an acid stop). Either way you end up in the same place and in the same final state.

So are you saying that you have access to R&D of Kodak, Ilford, Ansco, Rollei, Agfa, Luminere, ... and after reviewing all those documents, that you know more than all the photo engineers in history? You should stay away from sharp objects since if you get pricked you will explode.

SchwinnParamount · Jan 26, 2021

Rather than risk rapid, uncontrolled, and catastrophic deflation, I think I'll stick with Kodak indicator stop bath. It's not actually that expensive. Although, you know... water is pretty cheap.

JBrunner · Jan 26, 2021

I've never used stop bath. It's also well known my that my negatives and prints absolutely suck...

SchwinnParamount · Feb 10, 2021

Stop bath pH? What does too much or too little do to your gelatin? Ask Donald.

Donald Qualls · Feb 11, 2021

Stop bath pH is almost a fixed quantity -- acetic acid at anything close to normal 2% stop bath strength will have the same pH until it's virtually exhausted; the pH figure is different for citric acid stop baths, but again, it's virtually constant until well into exhaustion. With acetic acid stop baths, people sometimes add sodium acetate to the solution to give a reserve of acetate ions, extending life with little effect on pH.

Where this came up was in discussion on what might have cause reticulation in an image in the gallery that I commented on. Large pH swings can cause gelatin to shrink or swell, which can result in reticulation.

john_s · Feb 19, 2021

I haven't read all 932 posts, sorry, but this link is worth a read. Ryuji Suzuki used to post here, but not lately.

Stop bath doesn't need to be extremely acidic. A little sodium hydroxide can be added to it to make it not so extreme. Some thoughts in this old thread:

https://www.photo.net/discuss/threads/what-is-stop-bath-for.37251/

BradS · Feb 19, 2021

john_s said:
....Ryuji Suzuki used to post here, but not lately....

I greatly miss his participation here. Hope he is well.

pentaxuser · Feb 19, 2021

What puzzles me is a variation of what maybe exactly the same point that Alan Rockwood appears to be making, namely: If stop bath stops the developer action instantly and water stop bath slows most of it instantly and within x seconds has stopped it then unless x in x seconds is more than a few seconds how much difference does this make to the extent of the film's development? Most of my dev times are over 10 mins so does an extra 5 secs( to be generous) of development over 600 secs make a noticeable difference to the negs that result in a difference in the subsequent print that cannot be corrected ?

I haven't seen the scientific evidence yet but if it is out there can someone please provide it?

Thanks

pentaxuser

Tom Kershaw · Feb 19, 2021

I generally use two bath fixing for black & white film, so in that regime using a stop bath possibly / probably helps to protect the functioning of the fixer. I don't really see a disadvantage to using a stop (it isn't expensive)...

cliveh · Feb 19, 2021

pentaxuser said:
What puzzles me is a variation of what maybe exactly the same point that Alan Rockwood appears to be making, namely: If stop bath stops the developer action instantly and water stop bath slows most of it instantly and within x seconds has stopped it then unless x in x seconds is more than a few seconds how much difference does this make to the extent of the film's development? Most of my dev times are over 10 mins so does an extra 5 secs( to be generous) of development over 600 secs make a noticeable difference to the negs that result in a difference in the subsequent print that cannot be corrected ?

I haven't seen the scientific evidence yet but if it is out there can someone please provide it?

Thanks

pentaxuser

But the point of a stop bath is that it arests the image instantly. Water does not.

Kino · Feb 19, 2021

Yee Gawds, The undead thread arises and walks again!

Sirius Glass · Feb 19, 2021

We all know that stop bath with indicator is just so damned expensive!

john_s · Feb 19, 2021

cliveh said:
But the point of a stop bath is that it arests the image instantly. Water does not.

In my experience, a stop bath for FB paper prevents later staining. Maybe my metabisulphite stop bath helps wash out developer. I don't know, I just know what has been working for me since I started using stop bath instead of water. Maybe my water rinse wasn't long enough or maybe not always fresh enough. Anyway, I find the stop bath effective and quick.

pentaxuser · Feb 20, 2021

cliveh said:
But the point of a stop bath is that it arests the image instantly. Water does not.

Yes I agree but isn't that just restating what I already acknowledged about acid stop bath. My question which I was hoping could be answered remains as before, namely how much real difference to the negative over the average development time does it make and is this likely to be enough to make a difference that matters?

pentaxuser

pentaxuser · Feb 20, 2021

michael_r said:
I agree that if your development time is sufficiently long, the additional density built during a “water stop” is relatively minor.

Thanks that was I thought and in my experience for about 10 or more years of not using acidic stop in film development that has been what I had observed with my film. After trying water I saw no difference in the "behaviour" of the negatives which made me have to do anything different with the negative to produce the same quality of prints

I do wonder at times how this subject generates as much "wasted heat" as it seems to. It certainly is a Photrio "trigger point"

pentaxuser

MattKing · Feb 20, 2021

pentaxuser said:
I do wonder at times how this subject generates as much "wasted heat" as it seems to. It certainly is a Photrio "trigger point"

It is the same with any procedure that has ramifications with respect to the short term results (in this case, the particular roll of film) and the long term workflow (in this case, fixer efficiency and capacity).
Most of us don't develop enough film to be able to see the benefits of stop bath use with respect to the fixer efficiency and capacity. So not seeing the immediate, short term benefits, we have difficulty putting ourselves in the shoes of those who will see the long term benefits.

Vaughn · Feb 20, 2021

michael_r said:
I...
So there is the final answer - stop bath AND water rinse is best.
...

I do that occasionally in the Expert Drums. Especially if I have forgotten to measure out the fixer, or I need to quickly get its temp back up. Toss some water in there after the acid stop and let it turn until I have my shit together.

On wasting water. Go pee in the backyard and/or don't flush your toilet a few times after peeing and you are good...

If one uses a water stop consistently, then any 'extra' developing is automatically taken into account in one's developing time. Unless one is fixated on using only manufactures times no matter what the results are.

Sirius Glass · Feb 20, 2021

michael_r said:
I would argue “possible/potential” long term benefits, assuming the “water stop” is done badly. As an acid stop user, I would need to concede use of an acid stop is just faster and probably less wasteful of water versus replacing the acid stop with a thorough water wash (I prefer the term “wash” versus stop or rinse since that is really what it should be thought of as, and how it should be done). It could even be soundly argued if one is interested in maximum fixer longevity/efficiency/capacity ideally a typical acid stop bath should be washed out before fixing.

So there is the final answer - stop bath AND water rinse is best.
Edit: typos

If stop bath was useless Kodak, Ilford, et al, would not have spend money on R&D and marketing. It is time for your to accept things as they are and stop searching for a new reality.

Besides stop bath with indicator is just so damned expensive!

john_s · Feb 20, 2021

michael_r said:
......
So there is the final answer - stop bath AND water rinse is best.
.....

My summary from the 947 posts is that water is fine for film. Acidic stop useful to prevent staining of FB papers unless the alternative water stop is fairly long and fresh.

Sirius Glass · Feb 20, 2021

michael_r said:
Who said stop bath is useless? I use it all the time. You have a strange habit of not actually reading anything people write prior to responding. Either that or you have a serious reading comprehension problem. Or perhaps English isn’t your first language.

While I quoted you, as a questioner, it is aimed at the naysayers who only use water.

Don_ih · Feb 20, 2021

I doubt you will find any real-world instance where fresh water allows more visible development of film than acid stop. However, when enlarging, reusing the same water bath will add more developer to it and effectively turn it into a weak developer.

Stop Bath.. How important?

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