Stop Bath.. How important?

[alanrockwood]

Let me repeat the challenge I made earlier. Regardless of your opinion on this topic, we have had enough speculation and conjecture.

Show us the evidence.

 

[Mr Bill]

I am aware that Ron Mowery, PE, advised using stop bath for the C-41 development process. Thank you for posting that for others to see and learn.

I think your statement, as is, can be misleading. Without having looked up PE's comments on this l would guess that he is specifically advising for the case of a hand tank.

I personally see the use of stop bath in a C-41 process as something of a kludge, mainly to allow use in a less than ideal situation.

 

[Mr Bill]

Check out the instructions on using TF 4 fixers as the RECOMENDATIONS state "do NOT use stop bath" so I really don't think we should use the recommendations of someone else on the internet as fact. I do believe the instructions by the engineers of the chemicals are the best to use.

Regarding instructions by "the engineers of the chemicals," I would generally agree. But... it can depend on the application as well as the intended users. And depending on the experience and financial resources of said "engineers," there may be unforseen situations that don't play well with the original instructions. So the original product or instructions may be modified to deal such things.

But if the product isn't a big financial success then even the instructions might not be updated.

Kodak used to put out, I think every couple weeks, a small publication called TIPS (Technical Information for Processing Systems). It was intended for processing labs, and included the latest information and workarounds for newly discovered lab issues. Eventually this information would get into the instructions, and possibly the products would be modified to deal with same.

Given that even someone with Kodak's resources sometimes has to come back and revamp things one can see how a smaller outfit might have issues.

 

[SchwinnParamount]

If as you posted using water is so effective, why was so much money used in research and development for stop bath, as though there is no purpose for stop bath. There is a logical disjunction.

Because a water bath is actually a "slow down in-deterministically" bath while a stop bath is a "stop" bath. The folks at Kodak recognized two things: 1) some people like a predictable process and 2) some people who may not be orthogonal to the process people, liked to save a few pennies on their fix. Also, I am annoyed whenever I find that I've killed my fix before its time and I have to mix a new batch at 85 degrees and wait for the solution to cool down to 68 before I can process film.

 

[koraks]

with white vinegar, you need to keep track of usage or have a pH meter to be sure it's still acidic

Not really.

 

[Ian Grant]

Check out the instructions on using TF 4 fixers as the RECOMENDATIONS state "do NOT use stop bath" so I really don't think we should use the recommendations of someone else on the internet as fact. I do believe the instructions by the engineers of the chemicals are the best to use.

PE - Ron Mowrey- who was involved in formulating TF-4 recommended using an acid Stop-bath with it, he, he posted this here on this Forum. He'd seen Dichroic fogging without one.

Ian

 

[snusmumriken]

What I don't understand is why forum members get so worked-up about whether anyone else uses a stop bath or just water. If someone started a thread saying "I can't achieve consistent film development", or "My prints show yellow stains on drying", it would be reasonable and helpful to mention stop baths. But here it just seems a brown bread/white bread argument.

The cost arguments are plain silly. For instance, assuming someone uses Ilford paper and chemicals, buys individual FP4+ film, MG FB 8x10 paper in a box of 100 sheets, buys Rapid Fixer in a 5 litre bottle and stop bath in a 1 litre bottle, the breakdown of costs is as follows (accepting Ilford's figures on capacity):

Film (per 35mm 36 exp film)

Film £5.97
Stop bath £0.28
Fixer £0.08

Paper (per 8x10 sheet)

Paper £1.24
Stop bath £0.01
Fix £0.05

So whether you splash out on stop bath, or use water and accept less capacity from your fixer, the chemical costs are small compared with the film or paper (or - dare I say it - camera!).

Let's be honest, who routinely tests their fixer solution anyway? I certainly don't. I have tested prints for residual fixer in the past, and as a result my routine now errs on the side of extravagance rather than risk stains on my prints.

The issue is really whether you get consistent results with your film development; and clean uncontaminated fixing of your materials, particularly paper. If these things cause no problem to you, your routine is fine. And if someone else's different routine is fine for them, that's also good ... isn't it?

 

[Kino]

Well, at least it's not a political fight...

 

[Mr Bill]

Let's be honest, who routinely tests their fixer solution anyway? I certainly don't. I have tested prints for residual fixer in the past, and as a result my routine now errs on the side of extravagance rather than risk stains on my prints.

More than you probably wanna know, but an example of a serious processing lab, pretty large, operating under a stringent sewering permit, vs "amateur" processing...

Speaking from my long-ago lab background, we "tested" every new mix of C-41 fixer via a pH and specific gravity check. This doesn't actually test for "usability," but rather checks that the mix operator has not made a significant error.

Then, each morning we would have the processor operators pull samples from each of their chemical tanks. We'd do the same checks on each fixer tank, pH and specific gravity. (On our C-41 machines we ran 3 fixer tanks, counter-current flow replenishment, squeegees between each tank. This was an effluent control measure, to drastically reduce silver going into the wash water.) The specific gravity checks were an indirect way of confirming that the squeegees were functioning correctly - each tank runs in a different range. It's also a cross check on the replenishment rate.

Then, during the processing day, we'd run a control strip every two hours on each C-41 processor. The first one was before the machine was cleared to start up on production work, and a final one at machine shutdown. These strips have test patches to screen for fixer problems, so each control strip sorta doubles as a crude fixer test.

When the machines were initially set up, and periodically after that, we'd run silver analysis on each fixer tank. This would confirm proper operation of this part of the "effluent-control system."

There's more. Overflow from the first fixer tank goes into a collection system for silver recovery. This was a manually-run batch system using electrolytic silver recovery. We wanted to push it as low as possible, without "sulfiding," prior to "tailing." Because this is a fairly sensitive end-point, right on the verge of sulfiding the cathode, the operator would pull a sample for silver screening. Our chem lab would do a 2-minute test, then give the operator a time, in minutes (at reduced amperage) to finish up the cycle. (On completion that fixer gets sent to a tailing system.)

On occasion, especially if there was a problem with the electrolytic silver recovery, we'd run a set of chemical analysis at intervals throughout the process. These would include thiosulfate, sulfite, and silver content, all referenced against the total amp-hours of plating current.

That's about on our fixer testing.

 

[Sirius Glass]

I think your statement, as is, can be misleading. Without having looked up PE's comments on this l would guess that he is specifically advising for the case of a hand tank.

I personally see the use of stop bath in a C-41 process as something of a kludge, mainly to allow use in a less than ideal situation.

No, you are wrong. Go read Ron's posts and you will see that they are backed up by scientific research at Kodak. It also prevents color crossover.

 

[koraks]

No, you are wrong.

If you look at Kodak literature, you'll see that a stop bath is not mentioned for the C41 process - see e.g. the Flexicolor documentation in document Z131 here (page 2-1).

 

[MattKing]

No, you are wrong. Go read Ron's posts and you will see that they are backed up by scientific research at Kodak. It also prevents color crossover.

With respect, I recall that PE's recommendations for stop bath inclusion in the C-41 process were specifically designed for the low volume user who used individual tanks.
It is an adaptation to the standard process that helps improve results from C-41 when that process is used in a non-standard way - e.g. with a JOBO system or in steel Nikkor tanks or Paterson tanks.
Ron used it in his research work, because it was impractical to do testing work with short lengths of film running through commercial processors.
Mr. Bill is correct in that the higher volume commercial runs - for which C-41 was designed - don't benefit from stop bath.

 

[Sirius Glass]

With respect, I recall that PE's recommendations for stop bath inclusion in the C-41 process were specifically designed for the low volume user who used individual tanks.
It is an adaptation to the standard process that helps improve results from C-41 when that process is used in a non-standard way - e.g. with a JOBO system or in steel Nikkor tanks or Paterson tanks.
Ron used it in his research work, because it was impractical to do testing work with short lengths of film running through commercial processors.
Mr. Bill is correct in that the higher volume commercial runs - for which C-41 was designed - don't benefit from stop bath.

 

[SchwinnParamount]

What I don't understand is why forum members get so worked-up about whether anyone else uses a stop bath or just water. If someone started a thread saying "I can't achieve consistent film development", or "My prints show yellow stains on drying", it would be reasonable and helpful to mention stop baths. But here it just seems a brown bread/white bread argument.

I started this thread 17 years ago because there were several stop/water discussions going in APUG at the time. It seemed that people were passionate about one side or the other at the time. They still are. Also, I was relatively new in darkroom work and not entirely sure what was right either. I am a stop bath user because that's how I was taught by none other than Ansel himself. Yeah, I am old enough to have attended one of his summer workshops in Yosemite and eventually, a day in his darkroom in Carmel. He was a process man. Stop bath was one of the common elements in just about all of his recipes.

 

[Sirius Glass]

I started this thread 17 years ago because there were several stop/water discussions going in APUG at the time. It seemed that people were passionate about one side or the other at the time. They still are. Also, I was relatively new in darkroom work and not entirely sure what was right either. I am a stop bath user because that's how I was taught by none other than Ansel himself. Yeah, I am old enough to have attended one of his summer workshops in Yosemite and eventually, a day in his darkroom in Carmel. He was a process man. Stop bath was one of the common elements in just about all of his recipes.

Just after I finished grad school I had bought several lenses for my Minolta SRT 101 and was shooting slides. My coworkers has arranged two weeks of classes with Ansel Adams in Yosemite. I was so smart that I know that the Zone System worked for large format but not practical for roll film. Besides when one takes slides who needs the Zone System, so I took a pass on the classes. Years later I started kicking myself in the ass. I will let you know when I stop.

 

[SchwinnParamount]

Just after I finished grad school I had bought several lenses for my Minolta SRT 101 and was shooting slides. My coworkers has arranged two weeks of classes with Ansel Adams in Yosemite. I was so smart that I know that the Zone System worked for large format but not practical for roll film. Besides when one takes slides who needs the Zone System, so I took a pass on the classes. Years later I started kicking myself in the ass. I will let you know when I stop.

Damn it Steve, if you had gone to the classes in the summer that I went, we might have bumped into each other 40 years ago.

 

[npl]

A funny thing when you start b&w analog photography is to you think that after many decades of using pretty much the sames paterson tanks, films and chemistry, there would be easy straighforward answers to basics questions. Turns out, not so much. My top 3 is :

1. Prewashing
2. Stop bath
3. Dev time for Tri-X in HC-110 (b)*

*seriously kodak, 20 years later and the mistake is still there in the datasheet (https://www.covingtoninnovations.com/hc110/) ?

I've been on both side of the argument, not using a stop bath with film for the first year or so, then using it when I started darkroom printing, because the bottle with the mixed solution was right there. Ultimately, it doesn't matter much : even if development goes on for a bit with a water stop bath, your personnal development time with your personnal process will take that into account. And yes your fixer will be exhausted sooner, but that's not the greatest tragedy in the world..