What is the necessity using Chemical Stop Baths?

[Xia_Ke]

After a brief discussion on the topic in another thread, I'm interested on getting more opinions. Personally I use a Kodak Indicator Stop Bath. This is more just because this was the first method I learned about. I know some swear there is no need for it and just use water baths, while I've read of some just using vinegar. I've also read about some films that you should not use a stop bath with such as Efke's R25/R50 films. Just curious what everyone else uses and your thoughts on it's necessity.

Aaron

[photophorous]

Thanks for starting a new thread, Aaron.

I use a stop bath, but it's just water. Here's my understanding of stop baths. Obviously, they are intended to halt the effects of the developer after it is drained from the tank. Chemical stop baths do this immediately by neutralizing the developer. Water stop baths simply dilute and wash off the developer, and so the effects are not as immediate. I suppose the use of a chemical stop bath might be more important with more active developers...when your developing time is short. In practice, I don't know how much difference it makes. I think consistency is the key, because even if a small amount of development takes place after the developer is drained out, that will become part of your process if you do it the same way every time. Hopefully someone else can elaborate on this.

As far as I know, the only reason not to completely skip the stop bath step, is because your fixer will quickly become contaminated with developer, shortening it's life.

Paul

[mtbbrian]

Stop bath neutralizes the developer and stops the development process.
And "Indicator Stop Bath, changes colors when it is exhausted.

This is a better explanation:
After the prescribed development time, the plate is placed in a dilute solution of a weak acid (usually acetic acid), known as stop bath. Most developers are active only when alkaline, so the stop bath immediately halts the conversion of silver halide to metallic silver grains. It then rinses most of the developer out of the gelatin.

I found it HERE
Brian

[Xia_Ke]

Sorry guys, I meant the necessity of a chemical stop bath over just water. I edited the title to clarify that. I know that some form of stop bath is needed though to stop the development process. There are a lot of variations/methods used though and wanted to see what other use in their routines.

[mtbbrian]

As far as I know, the only reason not to completely skip the stop bath step, is because your fixer will quickly become contaminated with developer, shortening it's life.

Paul

Which in the long run will cost you more money!
$$$$$

Use a stop bath!
Brian

[mtbbrian]

You can use water, only if you have no other choice, but I would proabaly soup it a lot longer in a water "stop bath" than I would a chemical one.
Brian

[Xia_Ke]

Paul I know you mentioned in the other thread about two 30 second water stop baths. Now do you just let water run through your tank or do you fill with water and agitate for 30 seconds each cycle or...?

[mtbbrian]

Read this discussion from photo.net on using water versus a stop bath.
"Water instead of short stop when developing film"

Brian

[Xia_Ke]

Read this discussion from photo.net on using water versus a stop bath.
"Water instead of short stop when developing film"

Brian

That link isn't working :

We had a problem processing your entry:

Couldn't find message 004tHM.. It was probably deleted by the forum maintainer.

Please back up using your browser, correct it, and resubmit your entry.

[mtbbrian]

That link isn't working :

Hmmmmm?
It worked at first for me, but has been working off an on now.
Keep trying it too.
If you are familar with photo.net, look up stop bath there.
Find it by going through these options, Community > Forums > Large Format > Darkroom:film processing >
Maybe try this link too. http://photo.net/bboard/q-and-a-fetch-msg?msg_id=004N5n
Make sense?
Brian

[SmartWombat]

I never used a chemical stop bath, just water.
I just wash/drain several times before fixing.

[mtbbrian]

That link isn't working :

I see you changed your avatar!
Now we know who we are dealing with!

Brian

[photophorous]

Paul I know you mentioned in the other thread about two 30 second water stop baths. Now do you just let water run through your tank or do you fill with water and agitate for 30 seconds each cycle or...?

Immediately after draining the developer, I fill the tank with water and agitate for 30 seconds, about 1 inversion per second, then drain it. Then I do it again, but I'm not as careful to go for a full 30 seconds the second time.

Here's my logic (which could very well be wrong): As soon as you pour in the stop water, any developer that is on the outside of the film will be washed off and diluted to a point where it would take hours to actually effect the development. There is still developer that was absorbed into the emulsion, which will not wash off as easily. The time I spend agitating will remove most of it, but after 30 seconds or so, it's pointless, because that tiny amount of developer remaining inside the film emulsion will have exhausted itself by the time I'm through shaking the tank. So, I suspect a small amount of developing continues in the initial 30 second "stop" wash, but as long as I'm consistent with this process, it is factored in. I've never noticed any visible defects on my negatives, and I've never had a problem with premature death of my fixer. I hope there are no problems that I'm just overlooking.

Paul

[Xia_Ke]

Thanks Brian. That second article is a good read. Still can't get the first link to go through though

Thanks for chiming in Paul Good to see you over here :thumbsup: Just curious, was there any particular reason you used just water? Was it a preference thing or how your were taught or...?

[Xia_Ke]

I see you changed your avatar!
Now we know who we are dealing with!

Brian

There's a bigger version in my gallery titled "My Ugly Mug" if you need a closer look

[mtbbrian]

There's a bigger version in my gallery titled "My Ugly Mug" if you need a closer look

I'll just stay with the avatar view, Thanks!
You're in good company in that you, like the rest of (especially Paul) belong BEHIND the camera!
Just kidding Paul!
:thumbsup:

Brian

[Xia_Ke]

Immediately after draining the developer, I fill the tank with water and agitate for 30 seconds, about 1 inversion per second, then drain it. Then I do it again, but I'm not as careful to go for a full 30 seconds the second time.

Here's my logic (which could very well be wrong): As soon as you pour in the stop water, any developer that is on the outside of the film will be washed off and diluted to a point where it would take hours to actually effect the development. There is still developer that was absorbed into the emulsion, which will not wash off as easily. The time I spend agitating will remove most of it, but after 30 seconds or so, it's pointless, because that tiny amount of developer remaining inside the film emulsion will have exhausted itself by the time I'm through shaking the tank. So, I suspect a small amount of developing continues in the initial 30 second "stop" wash, but as long as I'm consistent with this process, it is factored in. I've never noticed any visible defects on my negatives, and I've never had a problem with premature death of my fixer. I hope there are no problems that I'm just overlooking.

Paul

Thanks for the explanation Paul

I'm curious about something though, are there any effects on final negatives going one way or the other? For example, will using a chemical stop bath give more grain or contrast over a water stop or vice versa?

[Xia_Ke]

I'll just stay with the avatar view, Thanks!
You're in good company in that you, like the rest of (especially Paul) belong BEHIND the camera!
Just kidding Paul!
:thumbsup:

Brian

Hey no picking on Paul. A beard like that NEEDS to be photographed

[mtbbrian]

Hey no picking on Paul. A beard like that NEEDS to be photographed

DOH! I forgot we had two Pauls in on this thread!
I meant "photophorous"!
I don't know the other Paul that well.
Brian

[SmartWombat]

I was doing all my own chemistry.
Made up to formula from the raw chemicals (cheap).
The Ilford manual didn't mention acid stop bath, and since the fixer I as using was acidic too, I saw no need for extra expense.
First a fill and immediate drain to wash off developer.
Then a 30-60 second soak to get some more developer out of the emulsion before moving on to fixing.

Now 35 years later some of the negatives show signs of incomplete fixing.
I think I carried on using fixer after it was exhausted, rather than mixing up fresh each time.
Several films haven't survived well.

[mtbbrian]

Thanks for the explanation Paul

I'm curious about something though, are there any effects on final negatives going one way or the other? For example, will using a chemical stop bath give more grain or contrast over a water stop or vice versa?

Now you are getting way over my head!
You might want to ask that on APUG.
Brian

[photophorous]

Thanks for the explanation Paul

I'm curious about something though, are there any effects on final negatives going one way or the other? For example, will using a chemical stop bath give more grain or contrast over a water stop or vice versa?

I've never used a chemical stop bath, so I can't say for certain. But, I don't think grain and contrast would be affected. I suspect there is no difference at all, but if anything, using a water stop bath might equate to adding a few seconds to your development...which you would probably never notice.

I'd be interested to hear from someone who has tried it both ways. Seems like most people just go with what they were taught and don't experiment much with stop baths.

Paul

[Xia_Ke]

I was doing all my own chemistry.
Made up to formula from the raw chemicals (cheap).
The Ilford manual didn't mention acid stop bath, and since the fixer I as using was acidic too, I saw no need for extra expense.
First a fill and immediate drain to wash off developer.
Then a 30-60 second soak to get some more developer out of the emulsion before moving on to fixing.

Now 35 years later some of the negatives show signs of incomplete fixing.
I think I carried on using fixer after it was exhausted, rather than mixing up fresh each time.
Several films haven't survived well.

Thanks Paul! I've thought a few times about mixing my own stuff. Chemistry was always one of my favorite subjects...LOL

Your post leads me to another question now What happens to film over time when it hasn't been fixed properly? Does it just fade?

[mtbbrian]

What happens to film over time when it hasn't been fixed properly? Does it just fade?

I don't know if fade is the correct term, I think it will show signs of discoloration, assuming it survives being exposed to light that long.
But you MIGHT, be able to fix and wash it again and it SHOULD be OK.
It's been a while since I have developed any film so I don't completely remember.
Brian

[photophorous]

DOH! I forgot we had two Pauls in on this thread!
I meant "photophorous"!
I don't know the other Paul that well.
Brian

Ah ha! So you were talking about me. I wasn't sure.

Yeah, I don't like being in front of the camera...especially when someone else is behind it. But, I did take a couple of mirror shots to finish up that roll of Neopan 400. I might have to participate next time Adina starts up the SP thread.

Paul