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Stop Bath.. How important?

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kimballmcgary said:
Take a penny and cut it up 8 times and tell me YOUR ART ISN'T WORTH IT.
Click to expand...

And never mind that stop bath (for film) will stop dozens of rolls. Practically speaking, it's free.

I may have to mix a fresh batch, not because the indicator has changed to show exhaustion, but because 120 Fomapan that wasn't presoaked left cyan antihalation dye in the developer, stop, and even the fixer (and still some came out in the wash water) and I can't see the indicator in the stop bath any more.
 
SchwinnParamount said:
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?
Click to expand...
 
"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? "

Another stop bath success story!
 
The guy who suggested agitation could be onto it. I have never experienced such issues with my 35mm negatives and use clean Nikkor reels, in a 4 reel can and anywhere from 1-4 filled with film. The procedure for agitation has served me well for 50 years. Every 30 seconds I spend 5 seconds inverting the can maybe about 3 times and then slap it on the counter top to get any bubbles out. If I am right, even the developers tell you to do that in their instructions.

Dan
 
This thread is like a never ending episode of South Park.
 
I have seen that difference in density too.
But, to my very personal opinion, it looks like the accumulation of non dissolved coloured anti halo layer which is, I think, normally dissolved by the acidity of the stop bath/fixing bath.
When that (slimy-) layer isn't totally dissolved, it slowly slides down to the end when the film hang to dry.

I managed to solve this by constantly agitating the water stop bath, during 2min, on a motorbase. Then the water comes out slightly coloured having the tint of that layer.

In all honesty, I have to admit to apply a pre-rinse, on a motorbase, for 10min (yes, while preparing the developer), then the water that's coming out is very, very, dark, nearly purple/black!
BTW, that long and intensive pre-rinse NEVER EVER caused any problems, not with Tri-X, Plus-X, Fp4+, Hp5+, FOMApan nor Bergger.
I discovered it rather by accident when called away on the phone and forgot about it for about 10min.

That's why, I think, that the colour of the water stop bath is due to the dissolving of the (little) remaining anti halo layer, because the pre rince didn't wash it all away (as it isn't acidic).
When I use an acidic stop bath, all the anti halo is gone in 30sec, regardless the kind of pre-rinse is applied or the film used.

But, again, these are personal findings (and opinions), yours may be different, as your circumstances can't be the same as mine...
 
Philippe-Georges said:
When that (slimy-) layer isn't totally dissolved
Click to expand...

FYI: antihalation dyes are not a separate layer, but dyes that are embedded into a gelatin emulsion. On 120 and sheet film formats, they tend to be embedded into the bottom / backside emulsion that acts as an anti-buckling layer. This layer remains in place after processing. Any slimy feeling is just the gelatin emulsion that stays on the film; it will be more slimy as the pH is higher (alkaline) and will feel less slimy when it's acidic, just like on photo paper.

The only exception is the remjet layer on cine films; these are indeed actual layers. But they're not present on regular photographic film, and are a whole different animal in terms of removal.

How and when the dyes wash out, depends on several process parameters and of course the actual film used. The dyes are a little more persistent on some film types than on others. I've never specifically tested if an acid stop bath (or acid fixer) makes the dye wash out quicker. It's conceivable, although I'd expect that the opposite is more likely. Very alkaline solutions will soften the gelatin layer, making it easier to wash out anything that's in there.
 
koraks said:
The only exception is the remjet layer on cine films; these are indeed actual layers. But they're not present on regular photographic film, and are a whole different animal in terms of removal.
Click to expand...

In case anyone else is suddenly concerned that they have overlooked something, as I was, there is no remjet layer on Eastman Kodak Double-X.
 
snusmumriken said:
there is no remjet layer on Eastman Kodak Double-X.
Click to expand...

As far as I'm aware, remjet is found only on color films that are intended for cine use. Kodachrome had it, but the same Kodachrome we used for slides was used in 8mm, 16mm, and 35mm cine cameras.
 
When I develop 35mm Tri-X in a SS tank/reel at home I use a water stop bath. When I develop the same film in a friend's darkroom I use Kodak indicator stop bath. I see no difference between the negatives, either on a light table or when scanning. However, I develop with Rodinal, which looks like Welch's grape juice when I pour it out after the developing time, so my experience may not be the same as others'.
 
koraks said:
FYI: antihalation dyes are not a separate layer, but dyes that are embedded into a gelatin emulsion. On 120 and sheet film formats, they tend to be embedded into the bottom / backside emulsion that acts as an anti-buckling layer. This layer remains in place after processing. Any slimy feeling is just the gelatin emulsion that stays on the film; it will be more slimy as the pH is higher (alkaline) and will feel less slimy when it's acidic, just like on photo paper.

The only exception is the remjet layer on cine films; these are indeed actual layers. But they're not present on regular photographic film, and are a whole different animal in terms of removal.

How and when the dyes wash out, depends on several process parameters and of course the actual film used. The dyes are a little more persistent on some film types than on others. I've never specifically tested if an acid stop bath (or acid fixer) makes the dye wash out quicker. It's conceivable, although I'd expect that the opposite is more likely. Very alkaline solutions will soften the gelatin layer, making it easier to wash out anything that's in there.
Click to expand...

Then I must be wrong in my findings.
Anyway, the problem was solved, by coincidence?

"...Very alkaline solutions will soften the gelatin layer, making it easier to wash out anything that's in there." that's why I don't use acid products but a water stop (and sometimes a buffered stop bath) and neutral-to-alkalic fixer.
 
koraks said:
Neutral fixers are generally quite heavily bufferred, so a little acid carryover doesn't affect their pH significantly.
Click to expand...

Not just neutral fixers - many of the slightly alkaline ones as well.
They need to be useful in a number of different workflows.
 
Philippe-Georges said:
couldn't an acid stop can change the fixer's acidity value?
Click to expand...

The easiest way is to test it with some litmus strips.
But personally, I really doubt that you will see any significant change in the fixer PH.
But if you're worried, you can just do a quick fill, shake and dump of the tank with clear water. That will get rid of most of the acid.
 
Xylo said:
The easiest way is to test it with some litmus strips.
But personally, I really doubt that you will see any significant change in the fixer PH.
But if you're worried, you can just do a quick fill, shake and dump of the tank with clear water. That will get rid of most of the acid.
Click to expand...

Till a certain extend, this is what I do after developing in a staining developer.
Then, I use Ryuji Suzuki's buffered stop bath (pH +/-6) containing Sodium Hydroxide which I thought didn't belonged in the fixer, so I rinsed for 2 min, after the 30 sec stop.
But I might be a bit over concerned...
 
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Philippe-Georges said:
a staining developer.
Click to expand...

Bear in mind that these don't require any particular care in terms of preserving the stain. E.g. acid stop and fixer won't remove the stain in any way.

Philippe-Georges said:
Ryuji Suzuki's buffered stop bath (pH +/-6) containing Sodium Hydroxide
Click to expand...

Along with something like acetic acid or citric acid, right? Just to be clear on this. A solution with just sodium hydroxide is (1) not a stop bath, (2) not buffered and (3) won't have a pH of 6.
 
koraks said:
Bear in mind that these don't require any particular care in terms of preserving the stain. E.g. acid stop and fixer won't remove the stain in any way.



Along with something like acetic acid or citric acid, right? Just to be clear on this. A solution with just sodium hydroxide is (1) not a stop bath, (2) not buffered and (3) won't have a pH of 6.
Click to expand...

Sandy King advises no acid stop/fixer to maintain the coloured stain.

Water: 600cc
Acetic Acid 90%: 60cc
Sodium Hydroxide (pearls): 25g
Fill till 1000cc with water = work solution
Be careful while mixing!
When measured it gives about pH 6, depending on the tap water quality.
Replenish with a 1,7% Acetic Acid dilution.
 
Philippe-Georges said:
Sandy King advises no acid stop/fixer to maintain the coloured stain.
Click to expand...

Some myths are hard to dispel. The stain doesn't suffer in the least from an acid stop or fix. It's just an old story that keeps perpetuating itself over and over again. Just like the one that says that the stain can be removed with selenium toner. King probably only made that comment out of conservatism, "just in case". He evidently didn't actually test it, because he would have found that the stain doesn't disappear or diminish if you use an acid stop, fix etc.

To stain, or not to stain – Acid and pyro developers – Koraks tinkers

tinker.koraks.nl tinker.koraks.nl



Yes, that buffer formula sort of makes sense. It'll make mostly sodium acetate with a little acetic acid to bring pH down to just below 7. It's actually not a really good buffer since the typical acetate buffer range is from 3.5 to 5.5 or so. This means that at pH 6, the buffering effectiveness will be limited when alkaline solution is added to it, as happens due to carryover of developer. It'll still be more stable than water, of course.

Philippe-Georges said:
Be careful while mixing!
Click to expand...

The whole process becomes a little less tricky if cleaning vinegar is used instead of glacial acetic acid. The formula would then change into:

Start with ca. 750 cc cleaning vinegar (typically around 7% acetic acid)
Add 25g sodium hydroxide pellets
Top up to 1000ml.

The hydroxide pellets are actually pretty safe to handle in my experience. I use them a lot. The glacial acetic acid is another thing; I don't have any around the house and frankly don't see the need for it either.


Philippe-Georges said:
Replenish with a 1,7% Acetic Acid dilution.
Click to expand...

Why bother replenishing this? I'd just dilute 1+10 or so with tap water and use one shot. It's dirt cheap.

Anyway, to each their own, of course. I wouldn't bother with all this for the lack of any practical purpose/relevance.
 
Philippe-Georges said:
Sandy King advises no acid stop/fixer to maintain the coloured stain.

Water: 600cc
Acetic Acid 90%: 60cc
Sodium Hydroxide (pearls): 25g
Click to expand...
All that makes is a solution of Sodium Acetate, a salt. It will work as a buffer so developer carryover won't turn the bath alkaline. But in the end it won't do much of anything.

And for this you get to play with Lye and Glacial Acetic Acid???? If this is what's desired just use vinegar and baking soda.
 
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