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Stop Bath Substitutes

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jimgalli

jimgalli

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I've run out of ordinary stop bath, and no, I don't have any vinegar in the cupboard. I do have a bunch of part B sulfuric acid hardener left over from Rapid Fix I never used. How would that work as a stop? This is for RC prints.
 
For RC prints, I would feel totally comfortable just using a post-development rinse in a tray of tap water before fixing. Going straight into the fixer would stop the development post haste, but rinsing first would lower the amount of developer carryover into the fixer.
 
If you use just a tray of still water as a stop, then go into a neutral or alkaline fix, you run the risk of fogging your paper or getting incomplete fixation. Also, if you use a metol developer, the metol will not be totally removed in this type of process.

If you use water, it should be running water, and if the fix is neutral or alkaline, leave the lights out (safelight on) for the full fixation time.

PE
 
Dektol and Rapid fix. So no Surlfuric acid fix then, tap water is best. That's what I'm doing as we speak. Thanks!
 
stop bath

I find the comments here very interesting. I am presently using TF-4 archival rapid fix from Photographers formulary and their literature suggests a "running water" stop for 2 min and cautions that the use of an acid stop causes the fixer to deplete more rapidly. Makes sense I guess. I usually put the print into a tray of still water and then use my hand sprayer to gently wash the print at the same time.
Would like to know from Photoengineer if this would be adequte to remove the metol from the developer. I haven't as yet noticed any fogging problems.
 
I've been doing a metol print dev (dektol), water stop (not running, but changed often) and TF-3 fix for RC paper for years. Fix for 2 min., first min with safelight on, 2nd minute with room lights. I haven't noticed anything. In fact, this is the first I've heard of this. I would also be interested in learning more.
 
In my tankline which starts with Acufine and ends with TF-4, I used water for a while, but since I was getting very short development times in the summer, I decided to add a 10% solution of sodium metabisulfite as a stop, which is one of the formulas in Anchell and Troop, and it seems to be working, and despite the acidity, hasn't caused an unexpected fixer crash.
 
Metol is an alkaline organic compound that is delivered to us as a sulfuric acid salt in powder form. When you place it in developer it is hard to dissolve in alkali whereas HQ is easy to dissolve as it is an organic acid.

In the acid stop, Metol dissolves happily, and in the TF-4 the HQ dissolves happily giving you the best of both worlds. TF-4 is so well buffered, it is able to survive the use of a stop bath. I have tested that and it works due to the high buffer capacity of the fix. Even if the pH drops, the fix still works. All you need is about 2x longer wash if the pH of the TF-4 drops below about 7.0.

PE
 
I think when I've measured fresh TF-4 it has a pH of about 8.0.

If it drops to 7.0, would you recommend adding, say, sodium hydroxide to keep the pH up to 8.0, for the purpose of maintaining a shorter wash time?
 
Sodium Hydroxide would do nicely. You could use carbonate as well or Kodalk. It would just take more of them. Kodalk would be better than carbonate.

Never ever add potassium salts to fixers.
 
Thanks for the advice.
 
pH, as David noted. Add and measure pH using pH paper or a meter.

If you cannot do this, don't try.

PE
 
Have I been doing it wrong all these years? I don't have a pH meter, just Edwal Hypo Check which probably doesn't account for pH. I never bothered to check for pH. I could add Kodalk, but how much and when?
 
ph measurement?

I often see refs to ph measurement as photoeng. did in the last post. What is a preferred way to accurately measure ph? Indicator paper was used in HS chem class but hardly accurate as I remember.... Is there a meter? Also is there a way to measure water hardness without the cost of sending out a sample to a lab? Two things I've often wondered about, so thought I'd jump all over this opportunity..... Thanks, Bill
 
When using liquid emulsion from Rockland, they recommend using a VERY dilute fixer as a stop bath (because the acidity of a normal stop bath will potentially harm the fragile emulsion, in their words). I forget the fixer/water ratio now. Perhaps that would be a good option? What say the experts? Can this be used for RC paper as well?
 
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Today's pH strips measure in small increments with 3 color tabs that change color to give you pH. The HANA meter is excellent and can be purchased new from the Photographer's Formulary.

Hypo check has no ability to measure pH whatsoever. It just tells you whether the fixer you have can still fix film or paper.

Thinking it over, another way to make the TF-4 alkaline is to add some Ammonium Hydroxide. Unscented household ammonia is 3% and should do the job provided the pH is not too acidic. Otherwise you would dilute your fixer.

PE
 
The Purpose of the Short Acid Stop.

The short acid stops recommended by Kodak and Ilford,
10 and 30 seconds respectively, are intended to convey
an acidic character to the film or paper. Acidic so that
the acidic fixers remain so. Although the developer in
in the film or paper is reduced by the stop it's
substantial reduction occurs in the fix.

If the fix is alkaline there is no point in using an acid
fix. A 30 second water rinse will do as well or better
at rinsing out the developer than Ilford's 30 second
acid stop.

Why worry about some little developer, what ever
it's composition, showing up in the fixer? After all there
are still post fix washings ahead. If the fixer is acidic
there should be no worry; note the very short acidic
stops which precede. Not so with an alkaline fixer.
The activity of any carried forward developer is
maintained. As the fixer's silver load increases
the chances of in solution reduction increases.
Silver may deposit on any surface. Dan
 
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