Water Stop Question?

[DanK]

I usually use a 'normal' dilution Stop Bath while developing...but, a new film I've been trying suggests water for the Stop, first few runs I tried an extremely light iflostop/water dilution....

But, this last time (minutes ago) I decided to try straight water as the Stop (as recommended) - while sitting in the dark, I began to wonder what the effects of using straight water as a stop are....essentially the developer is only 'diluted/diffused' not 'stopped'....

So what part of the negative is the 'diluted/diffused' developer working on while in the plain water stop bath?

My guess would be that the 'diluted/diffused' developer would continue to work on the highlights, in similar fashion to a water bath during development, but would like a few opinions if possible....

Thanks,
Dan

[Gem Singer]

You're correct, a plain water stop bath works the same as a water bath.

Developer that is carried over in the emulsion layer will continue to develop in the highlight areas until it exhausts.

However, the carried over developer is diluted and rinses out very quickly after a few seconds in a plain water stop bath. There is only a slight compensating effect.

An alkaline fixer is recommended when using pyro developers in order to maintain the stain.

However, if you are using a conventional developer and an acidic fixer, there is no advantage to using a plain water stop bath.

[DanK]

Thank you for the quick reply....

It's actually a conventional developer that I'm using (D76 stock) with the Adox Pan 25 film.

I am unsure as to why they suggest a water stop for this film - apparently due to the formulation or thickness of the emulsion...

Thanks again,
Dan

[Gem Singer]

Dan, perhaps a plain water stop is recommended in order to prevent an acid-base reaction when moving the film from an alkaline developer to an acidic stop bath.

The formation of carbon dioxide gas bubbles that could possibly cause pin holes in the the emulsion of that particular film.

[DanK]

Thanks again for the quick response....

That makes sense to me, although I am not sure of the difference between that particular emulsion and modern emulsions...

You (Gem) also mention no advantage to using a water stop with conventional developers - is there a potential disadvantage to using the water stop with conventional developers and modern film emulsions? I tend to set up one batch of tanks and develop a couple different films over an hour or two - this time was adox first, then FP4 - also with a water bath, rather than acidic stop.

Dip and Dunk - 2.5L tanks

PreSoak 1-2 min
Developer D76 stock
Water Stop 1 min agitated
Ilford Rapid Fix 1:4 (5 Min)
Water Soak 5 min
Wash - 40min
Photo-Flo 5min
Hang

Is there a potential for problems with the FP4 and water bath, that you may be aware of?

Thanks again,
Dan

[Gem Singer]

No potential disadvantage to using a plain water stop bath with conventional developers and acidic fixers, except that a small amount of developer is carried over with each sheet of film and will exhaust the fixer after a few uses.

I find the slight compensating effect of the plain water stop to be an advantage.

For developing paper, especially fiber base papers, best to use an acidic stop bath because a larger amount of developer is carried over and will exhaust the fixer very rapidly.

No potential problems with FP-4+. Ilford uses a hardened gelatin for FP-4+. I believe that the gelatin of the Adox film is not hardened.

[DanK]

Thank you again, Gem Singer, and I must say I really appreciate your time...

I have a 'Love' 'Hate' relationship with new films....Usually love the results, hate getting there....

Love FP4, but need a slower film for an older Rapid Aplanat (wide open)....

As yet, it looks like the Adox will do the trick, but I like to shoot the same subject with a standard shuttered 150 (on FP4), as a back up, and I'd hate to be hurting the backup with the water stop....

Thanks again,
Dan King

[mikew]

I usually use a 'normal' dilution Stop Bath while developing...but, a new film I've been trying suggests water for the Stop, first few runs I tried an extremely light iflostop/water dilution....

But, this last time (minutes ago) I decided to try straight water as the Stop (as recommended) - while sitting in the dark, I began to wonder what the effects of using straight water as a stop are....essentially the developer is only 'diluted/diffused' not 'stopped'....

So what part of the negative is the 'diluted/diffused' developer working on while in the plain water stop bath?

My guess would be that the 'diluted/diffused' developer would continue to work on the highlights, in similar fashion to a water bath during development, but would like a few opinions if possible....

Thanks,
Dan

Hey Dan...I know this a little after the fact but I wanted to echo Gem's advice and clarify one point:

When film is transferred from the developer to a water stop bath the developer does indeed get diluted. However, the effect of this is that the developer rapidly exhausts in the highlights, but continues to develop in the shadows, albeit for only a few moments. Both highlight compensation and adjacency effects occur. At any rate, the effect might be negligible but I thought that it warranted mention.

The important thing is that you allow for a slight time adjustment to your development - a slightly shorter development time - and that you drain your negs for 10-15 seconds when pulled out of the developer and when pulled out of a water stop bath of running water (or a water bath that cycles water 5 times in one minute). Remember that within 10 seconds of a negative being drained - after the developer - about 14 ml of developer is left either on the surface of the film or is absorbed into the emulsion (for 80 square inches of film).

Best of luck!

Mike W

[DanK]

Thanks Mike....I appreciate the response....

I didn't consider continued development in the shadows....

Also, I use tanks, and didn't consider that much carry-over, as I've often used the same water bath (not a running bath) for multiple runs...which will now be be fresh bath each run....

Thanks again,
Dan