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Stop Bath.. How important?

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CMoore said:
Anybody know how "Exhausted" the indicator fix is when it starts to turn Black/Gray.?
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It turns purple.
You should discard the fix when you can see the colour change.
I use white trays for stop bath, so I can see.
 
Agree with Matt. The indicator immediately turns purple when its indicated pH level is reached. We used SS trays, but if you tilt the tray, the stop bath is noticibly darker when purple. Does exhausted indicator fix becomes a water bath? :cool:
 
MattKing said:
It turns purple.
You should discard the fix when you can see the colour change.
I use white trays for stop bath, so I can see.
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Vaughn said:
Agree with Matt. The indicator immediately turns purple when its indicated pH level is reached. We used SS trays, but if you tilt the tray, the stop bath is noticibly darker when purple. Does exhausted indicator fix becomes a water bath? :cool:
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Ah.....OK.
I only saw it happen once, in class. I thought it was kind of a black, but we were in safe-light....never saw it in normal light i guess. :smile:
 
Vaughn said:
Agree with Matt. The indicator immediately turns purple when its indicated pH level is reached. We used SS trays, but if you tilt the tray, the stop bath is noticibly darker when purple. Does exhausted indicator fix becomes a water bath? :cool:
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Perhaps. I used a tray washer (on a low flow), so developer in my water stop was never an issue. Note that I find no fault with an acid stop. It has advantages for some situations. This is clearly an issue of situational and personal preferences.
 
Vaughn said:
The indicator immediately turns purple when its indicated pH level is reached.
Click to expand...
If you want to see something purty, at the end of the developing session, if you intend to discard the solutions anyways, mix the stop bath and developer together first.
It probably won't work with Amidol :smile:.
With respect to Vaughn's observation, if you are using a white or cream coloured tray, you will probably be able to notice a change in the colour of the stop bath from yellow to neutral colour immediately before the turn to purple.
 
CMoore said:
Anybody know how "Exhausted" the indicator fix is when it starts to turn Black/Gray.?
Click to expand...

I don't remember precisely, but I can look it up easily.

The indicator used is bromocresol purple; Google quickly reminded me that it's yellow below pH 5.2, and turns purple above pH 6.8 (which will look black under amber safelight). This is conveniently very close to the neutral pH 7, so if your indicator stop bath has lots its yellow color, it's approaching losing its acidity as well. I have no doubt this is most of why this indicator was chosen, though the actual color (transparent under red or amber safelight when acidic enough, dark when not) might have made a decision between this and other indicators with similar ranges.

If you have indicator fix you may have grabbed the wrong bottle at some point, and should test run a residual halide test on any prints you've made since the last time you mixed your chemistry...
 
Donald Qualls said:
I don't remember precisely, but I can look it up easily.

The indicator used is bromocresol purple; Google quickly reminded me that it's yellow below pH 5.2, and turns purple above pH 6.8 (which will look black under amber safelight). This is conveniently very close to the neutral pH 7, so if your indicator stop bath has lots its yellow color, it's approaching losing its acidity as well. I have no doubt this is most of why this indicator was chosen, though the actual color (transparent under red or amber safelight when acidic enough, dark when not) might have made a decision between this and other indicators with similar ranges.

If you have indicator fix you may have grabbed the wrong bottle at some point, and should test run a residual halide test on any prints you've made since the last time you mixed your chemistry...
Click to expand...
10-4..... Thank You :cool:
 
Tyler Longfellow said:
I've had great luck with no stop bath
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not necessarily you but this is the classic case, the kind of situation where, in a few years, your prints start degrading and you can’t tell why and you’ll never be able to trace it down not using a stop bath.

But of course, the real reason for the degraded prints would be bad fixing because of a prematurely exhausted fixer caused by the carry-over of developer. yes, even a partially fixed print/film looks good at first.
The surprise hits you when you revisit your work a few years down the road.

“I don’t understand, I always used fresh fixer, that can’t be it. I will have to ask on the internet...”
 
NB23 said:
not necessarily you but this is the classic case, the kind of situation where, in a few years, your prints start degrading and you can’t tell why and you’ll never be able to trace it down not using a stop bath.

But of course, the real reason for the degraded prints would be bad fixing because of a prematurely exhausted fixer caused by the carry-over of developer. yes, even a partially fixed print/film looks good at first.
The surprise hits you when you revisit your work a few years down the road.

“I don’t understand, I always used fresh fixer, that can’t be it. I will have to ask on the internet...”
Click to expand...

So what that the photograph faded, look at all the money he saved on stop bath.
 
It's alive!!!!!!!!!!!
 
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?
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My experience with water has been very positive. I allow fresh water to flush through several times.
 
drfoxmd said:
My experience with water has been very positive. I allow fresh water to flush through several times.
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snusmumriken said:
Maybe you don't realise, the OP started this thread about his problem 17 years ago! A lot of water has flowed through the tanks since then.
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[sarcasm] So has stop bath and we all know that stop bath with indicator is just so damned expensive that its cost can prevent some people from using film. Perhaps it should be illegal for people to use stop bath. Will @drfoxmd be willing to sign petitions outlawing the use of stop bath based solely on his meager experience? Look at all the money that film manufactures wasted on research and development on stop bath! Obviously these companies do not know what they are doing and the companies therefore should go out of business![/sarcasm]
 
Indicator stop bath is good. You can vary the dilution and when turning purple discard. Don't scrimp on cost for such basic chemistry.
 
snusmumriken said:
Maybe you don't realise, the OP started this thread about his problem 17 years ago! A lot of water has flowed through the tanks since then.
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Ah..., but was it acidified or just plain water, and did it make any real difference?
 
alanrockwood said:
Ah..., but was it acidified or just plain water, and did it make any real difference?
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Yes.
  • It stops the development completely
  • It keeps the fixer from getting polluted, thus lasting long
  • It helps prevent staining
For starters. The film and photochemical manufactures knew that stop bath was needed and worthy of R&D plus they know a lot more than most of us.
 
Water stop & TF3 fixer you can mix yourself. Support your local/regional/national photographic chemical supply outlets 👍
 
Sirius Glass said:
We all know that stop bath with indicator is so damned expensive!
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Oh heck yes. A bottle of stop bath concentrate might cost me $10 at my local shop. That bottle represents a couple hundred gallons of working solution. 100 gallons of water? less than $10. If I was struggling to buy a latte, then yeah, I'd go with the water bath... if I didn't care about the longevity of my fix. Oh yeah, that. Fix is more expensive than stop by a fair amount.
 
Wow, we're nearing the 20 year marl on this thread! Short answer: film no, paper yes (only to keep the fixer alive longer).
 
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