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Acetic acid as stop bath for film?


I sort of suspect that a lot of people who develop film
(not only photographers):

1.
Do not keep (sufficiently) accurate records to track down problems back to their true causes.

2.
Use a variety or mish-mash of methods and materials over their productive lives.

3.
Process somewhat differently depending upon the work load
(total wet times depend on prints being processed, etc.)

4. Do not monitor their fix and wash cycles all that accurately/consistently over their careers.

5. Do not monitor negative condition, nor have sufficient means to quantify
any changes that might occur.

While individual photographers (this means you/us) may not have any problems to speak of, I think the person's opinion we should seek out is that of the professional conservators and people who work in museums and places that have large collections... and are sort of in the business of keeping an eye on such things... They probably have examples of some of the problems that occur... yet for reasons mentioned above, I doubt they can say much about their actual causes either.

As an aside,
I have examples of CIBACHROME problems...
(the dyes are excellent...
but the paper base has yellowed so much it is neauseating!

I followed mfg's instructions to the letter, no short cuts.
Still problems developed.
Who knows what the cause was.

The only point being that there are enough unknows in the life and storage of materials as it is
and if potential problems are understood,
isn't it desirable to minimize them?

Yellow stains or other trouble may or may not present a problem.
But I think it is a better goal to strive to secure a negative that doesn't change at all, rather than one that might change but not in a way that would affect later printings in a worrisome way.

People used to use water, but reported problems so some manufacturers developed and promoted stop baths to eliminate those problems. Now other people who have never experienced those problems want to go back to plain water. Since the materials in use today are different maybe it is OK. Who knows?

It is a personal judgement call, not worth all this discussion.

Perhaps time will prove stop baths were inferior to a plain water rinse! :alien:

If I am correct, most people who do have a problem may never know it.
I imagne there are exceptions but I just don't think most of us keep that close a watch on our processed negatives.

Manufacturers know of many problems as they regularly test and get told of many problems by those who use their products... They also hold onto samples many years after manufacture.

On a visit to the Harman factory, they had samples of processed tests laying around one of the rooms visited... We were shown how good their production was and how hard they try to eleminate problems...

I commented that was nice, but would like to see examples of some problems they had found... this light hearted request was cheerfully turned down.

Perhaps Manufacturers are not all that keen to show us their used toilet paper?

In one or two images in Shanebrook's book however, you can see that they have sample (unrelated) problems for operators to refer to. So, such things do exist.

This is not to say that I am supporting any particular claim or whatever.
Certainly, some "problems" may have had causes that were rooted elsewhere than once thought.

I am just saying that birds and squirrels eat cautiously for a reason.
 
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Ray, it's a case of taking a statement out of context.

Mason clearly says that a Stop bath is superfluous, and he then says under what circumstances, no ones disputing that.

The important issue which has been missed is that I've never said we should emulate missing out the step but pointed out that Fuji & Kodak do in fact miss out the step.

So in that context the step is superfluous, but we know it has benefits as far as we are concerned which I meticulously listed.

I've also said all along in two threads now that Mason's saying the step is superfluous (regardless of his caveats) merely highlights that it's less important to the removal of developer and its byproducts in an emulsion and the long term stability than is assumed. The fact that both Kodak & Fuji make machines for B&W film & RC papers with no facility for this step support the superfluous nature of the step.

Far too much importance is given to those comments which are correct particularly when taken out of the context of what I wrote in full.

Ian

 
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Hi Ian,

Certainly the machines you refer to are an important consideration; which machines and especially, the reasoning that went into their design and particularly, why that step was omitted should be examined and addressed.

I haven't a clue, but I did observe a subtle attitude adjustment where Kodak seems to have more firmly embraced the "it's acceptable" rather than "it's ideal" philosophy.

If this had anything to do with the machine design you refer to, I don't know, but I do not think you should discount it out of hand. I have never thought of those huge processors as being truely "archival processors" anyway....

Ray
---

(P.S.: Thanks for your help with the free pdf maker software a week or so back...
Everything worked out well!)
 
I find it interesting to see what a lengthy discussion my question sparked. Anyway, I am now using Acetic acid diluted 1:30 and it works fine.
 
Summary from what I've read and what everybody seems to accept:

Any bath (water OR acid) to improve fixer life especially with neutral or alkaline fixers.

Acid stop bath for maximum stopping speed for maximum consistency in some cases (larger films and developer volumes).

And; everything works quite well, even leaving the whole step out, but it is considered good to use either an acid stop or water rinse.
 
First point is that a stop bath or water rinse will improve the life of any fixer regardless of type acid, neutral or alkaline. (As long as the alkaline fixer is well buffered then an acid stop bath is OK, some manufacturers say DO NOT USE an acid stop bath - I'm not referring to TF-4 or 5)

Second point is it's more about volume and type of tank than film format, so 5x4 LF sheet film in a Jobo tank (early non rotary), CombiPlan etc, or a 10x8 sheet in a tray would be OK with a water rinse or a stop bath.

However a Jobo Rotary tank (and similar), or large Deep tanks are far less suitable for a water rinse, the rotary tanks use too small a volume and a large deep tank would need far too much water, So in both these cases a stop bath is more practical.

The third point leaving the stage out isn't really a wise option from our point of view, yes it'll work but the risks of problems are too high. In commercial processors the films (and papers) are squeezed between rollers to remove excess carry over and the fixers may have extra buffering capacity etc, the transport mechanism takes the film rapidly from one bath to the next it's not like slowly hand-filling a tank.

It's not such a simple choice and so needs careful thought in making a choice.

I'm more than happy to use a water stop in my Jobo 2000 series tank for 12 sheets of 5x4 or 3 120 rolls and I know it works perfectly, I've been doing it for quite a few years. The initial decision was made because I was flying with film, chemistry and a tank and need to keep weight etc to an absolute minimum. When the limit is 15 or 20 Kg litre bottles of chemistry are highly significant, I actually make up developer concentrate at twice the normal concentration, so taht helps, fixers hot so easy.

No way would I suggest a water stop in a rotary tank as there's insufficient dilution, the step would need repeating and so it would be far easier to just use an acid stop bath.

We haven't really given much thought to these parameters but they greatly influence which choice should be made.

Ian
 
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Just a passing note on chemistry:

Most developers are basic, with pH from around 11 down to 9 (amidol developers being one of the few exceptions, they work in acidic conditions)
Water is "neutral" at pH 7
Acid stop baths which is diluted acids have a pH around 4 up to 5
Concentrated Acids have a pH around 1

Now compared to a basic solution of developer with a pH of 11, plain water IS an acid!

This is a floating scale, and one solution is rated in relation to the properties of the next bath.

A developer of pH 11 usually is stopped cold if the film is put in contact with water at pH 7, since this quickly neutralises the accelerator (soda or comparable stuff) that makes the developing agent work.

Inside a tank remains about 30ml of developer, after the tank is carefully emptied, dilute that with 600ml of clean water at ph 7, and the ph IS 7 in the tank, and very quickly in the film emolution too.

Same with (slightly) acid fixers.

I've used both in my life, usually when I have time, and/or money I get a proper stop bath. But if not I rinse with water, being thrifty and want to save the fixer as long as possible (I test that with snippets of film in broad daylight).

However at times when I used concentrated deveolpers, with very short developing times, I always felt it was absolutely necesssary to have a stop-bath at hand, that could stop development in its tracks, making the process controllable and repeatable at all, a stopbath that COULD be thrown away in the heat of action, while the fixer was a valuable asset!

These days I usually use developers that are diluted with long dev. times, and probably, this negates the stop bath, but being thrifty, as mentioned, I use it still, to save my fixer!

The only problems I've had in my nearly 50 years carreer as a film developer, is problems I think was related to final wash, but that was a long time ago, and who really knows, after the fact? Since then I've adapted a strict regime of dilute and dump watering, using 6 or 7 changes of water which guarantees a final rinse in a water almost 100% free of thiosulphates.....

Erik
 
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Eric;

On some of the pages of Haist that I did not scan and post earlier, he goes into detail describing the difference between pH and buffer capacity. Your argument about water is true regarding pH (actually, we find that water may be as low as pH 6 due to CO2 absorption or as high as 9 from additives or local mineral content), but water has zero buffer capacity! So, the buffer in the developer generally trumps the water regarding any change or at best the rate of change in pH that may take place in most cases.

Ray;

Ammonium vs Sodium fixers are mainly different in fix rate and to some extent in wash rate and not in any other effect.

PE
 
Ian Grant said:
No way would I suggest a water stop in a rotary tank as there's insufficient dilution, the step would need repeating and so it would be far easier to just use an acid stop bath.

Ian
Click to expand...

Interestingly, Phototherm (aka Photo-Therm, an automated rotary processor) uses a plain water for a stop bath for a minute thirty seconds for their black and white processing program.
 
alanrockwood said:
Interestingly, Phototherm (aka Photo-Therm, an automated rotary processor) uses a plain water for a stop bath for a minute thirty seconds for their black and white processing program.
Click to expand...

Although it might not appear that way I actually err on the cautious side, I'm using a minimum of 2 litres of water for 12 sheets of film (3x 120) where a rotary processor uses significantly less.

It would also depend on whether the Rotary processor was using the fixer "One shot", if so it doesn't matter as there's no necessity to help prolong the fixers life

Ian
 

On the surface that seems to be true, but not in practice!

Because theres a 1/20 difference between the developer rests left in the tank and the neutral water diluting it.

You will have a hard time proving that the buffer capacity of a simple developer is better than 1/20!

Besides, theres no need to get down to pH 7, it is more than enough to bring the pH down from a little under 11 to around 9, to stop developing action......

Water is a stop in itself, acid water is a better stop, simply because it works faster.
That helps maintain prescise control if the bath times are short.

However as in averey walk in life "fast" brings with it problems, and I have noted with interest arguments on both sides in this debate, that I think are valid.

Your argument that I need not go all the way to 2% acid solution in a one-shot discard stop-bath, is both convincing and on the ball, and I will act on it, since saving is GOOD, and since probable prevention from gas bubbles in the emulsion is even better! (bringing the stop bath to 1% instead of 2% brings the pH closer to pH of course, which only underlines my argument!)

PS my argument is for standard tank development, 135 and 120 film only, I know nothing about modern-day new-fangled rotary machines and motordriven processors!

Erik
 

Ammonium thiosulphate fixers have very significantly faster fixing rates than their Sodium equivalent so there's far less chance of problems with reasonably fresh fixer.

Older pre-1960'ish Rapid fixers are quite different and they used Sodium Thiosulphate and Ammonium Chloride to form Ammonium Thiosulphate in solution, they weren't as good as modern rapid fixers so can't be compared as equivalents.

Agfa published a Rapid fixer formula at least 100 years ago and sold them commercially. Hans Windisch in "The New Photo School 1938" states that the Rapid acid fixing bath (with Ammonium Chloride) is "more quickly exhausted than the acid fixing bath"

Modern Rapid fixers have far better capacity, and buffering, this is of huge importance for re-use.

So it almost certainly does change the essentials of those German comments, and is why Neutral/Alkali Rapid fixers are in vogue today.

Ian
 
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Eric;

I refer you to Henn and Crabtree, PSA J 17B:14 1951. Or Haist, VI P 542.

Neutralization time at pH values of 3 - 6 vary from about 15 sec to 90 sec (1.8% HOAC pH adjusted by unspecified means). OTOH, total acidity (units not specified) from 1 - 10 vary neutralization times from 30 sec to about 1 sec at constant pH (4.8). These values are at low agitation. High agitation decreases the times.

The accepted optimum is 1% - 2% for 60 seconds - 30 seconds. You can see how this fits with the above extracted data. These measurements were done using film dyed with an indicator which changed color as a function of penetration by the Stop after being transferred from the alkaline dye solution to the Stop then being tested.

So, it is not just developer in the tank, but the alkali in swollen emulsion that must be considered.

PE
 
I was thinking of the swollen emulsion too, and its interesting the absolute STERLING work those oldtimers did!
Think about that referred to as a "time they didn't have no technology"!

I worked with some of those oldtimers in the lab here, during the time I attended school. They did stuff quite naturally that it takes forever to explain to today's young, IF they grasp it in the end. They coludn't maybe measure down to 0,000000001, but they knew how to rule out, and prove being right, what had absolutely no chance in real life.

The swollen emulsion concept is what is hard to understand for people who think final rinse is just a question of "flushing out the fixer"!
 
Ian I re-read Windish on this immediately after reading your latest, yes, you quote him right.

Windish has a lot of other gems packed within some few printed pages there, I think a few pages' quotes could boost this discussion forever!
 
Eric;

Talking about oldtimers, I knew Dick Henn and worked with Grant Haist, who was in Dick's department. Dick and I used to meet in his office and talk about these types of experiments. He kept trying to get me to leave the Color Division and come to the B&W Division and work in his department. He was a grand old guy. Eaton was also in that department, and I had met him on a few occasions, but IIRC he was about to retire or had just retired. He was actually writing the chapter on Stops and Fixes for Howard James at that time for the revised version of Mees which was to become Mees and James. At that same time, I was one of the editors for Grant's book.

At the time I worked with them, they were pushing the new Bimat Stabilzed film for space imaging. Right now, one of the Bimat imagers is on display at George Eastman House. They were also working on heat processing and that is how I got involved, as Grant and I were working on a thermal color material based on Dye Bleach.

A slight digression, but it does help explain my heavy involvement in many of the Stop, Fix and Stabilization processes and my knowledge of what is in the literature in this regard. One point in this is relevant. No HQ or Metol derivative could be used in these stabilization processes due to the stain. They had to use phenidone derivatives! And this goes back to Grant's comments on retained HQ having the potential to cause stains as he mentions in his book.

PE
 
Interesting, thank you, you struggle with the same engineers do across the world, taking things out of the lab, explaining it coherently to laypersons in an understandable manner.

Many times I have had the pleasuree to talk with some of these guys personally, and getting the knowhow straight, in everday language, without constraints and with a lot of enlightening digressions. Its fascinating how much better we all are explaining something first hand, with body language, and subtle nuances in the language, than constrained by printed matter and publication dates or the dang keyboards we have to use here.

I'd love to take both you, Ian and many of the fellers in this discussion to the family's log-cabin, have a huge bonfire out in a half-lighted northern summer night and toss ideas, discuss the matter to the bottom of a 5 gallon jug of traditional norskie moonshine!

Nice weekend to all!
 
Great idea Erik, as my mate Stoo says (on APUG) "Ian shares his knowledge . . . . . . . Richard listens and takes on board all that Ian has to share. Ian is a natural teacher and without knowing it, talks through all that he does and touches. I think one day his head will explode .

All I ask is any meeting is prior to that explosion

There's more than one way to skin a cat, and that's the same with B&W processing.

Ian
 
Here is another idea Ian. Just as Dave Vestal and Al Weber teach workshops together (and argue sometimes - well, disagree strongly is a better way to put it - on some topics) we should do the same. That might be a good way to solve the world's energy problems at the same time by generating a non-nuclear high power, nearly explosive combination.

And, we teach analog photography. Well, just a thought.

PE
 

I too use a Phototherm. And I replenish my recovered Hypam at 115% of Ilford's recommendation.
 
Ian

I don't have Hans Windisch / "The New Photo School 1938"
Erik mentioned it would be good reading....

I would like to see it if you or Erik can get a few pages scanned.

Not sure I follow...
Why do you think Neutral/Alkali Rapid fixers are in vogue today?
 
Ray, the Windisch book is a nice publication, it only has a little in the way of chemistry, it does have the formula (and variation) that we now call the Windisch surface or compensating developer, which he doesn't actually claim to be his own formula.

It's more important because it was a primer essentially aimed at 35mm workers where a new approach was needed to get the best from film. My 1938 copy in English has some interesting adverts, 2 pages of Kodak (London), including Kodachrome, Leica, Robot, Zeiss - Contax, also lenses, and many pages of Gossen meters - with an emphasis on shooting, one photo is a hand holding a pointed pistol alongside another with a light meter

I haven't a scanner but will get something to you next week.

Neutral/Alkali fixers are in vogue because people are promoting them, in books and articles

Ian
 

He he, I'm referring to a translation into norskie, which is some kind of redneck rebel spoken backasswardedly.....

Norwegian translation says on the cover :

Hans Windisch : Den nye fotoboken med over 200 illustrasjoner hvoraf 24 helsides plansjer. Dreyers forlag Oslo efter 12. omarbeidede opplag 1956...........


And that is just for starters!

There are impresssive early electronic flash pictures coming out of the labs, among others of a cat in midair claws ready coming down on a mouse, needle sharp image, those goys where GOOD!

And another pistol picture, one guy firing a 1935 Beretta 9mm Kurz pistol at a shorting string, bullet caught in mid-air, apparently the bullet set off the flash, since I have one of those pistols two things catch my eye, the shooter has his eye too damn close to the end of the pistol, and is about to have his glasses broken from the recoiling slide, and the other is the picture data : 1/1000 sec @ f:22 which I think is a damn lie, no bullet would be caught mid-air at 1/1000th, only an electronic flash would do that, and it would be nearly pointless to use such a short speed in conjuction with a flash, impossible if it was a Leica or an Exacta, since flash synced around 1/20th back in those days.... its an impressive picture nontheless.

All this in norwegian, but I have HW's book on color photo in german language though...
 
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A fast flash does not need a fast flash synch speed.
 
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