Well, it kind of depends on buffering. For example, PE stated many, many times that both TF-4 and TF-5 could be used perfectly well with an acid stop bath.
Of course there is nothing wrong with doing water rinse after an acid stop bath.
And a water stop bath is not bad either, unless it isn’t thorough enough when using an alkaline fixer, in which case development could potentially re-start in the fix.
I agree totally. Also a well buffered alkaline fixer won't require the acid intake from carried an acid stop bath to stay ok.
Only
one addition, in case we use the efficient double Fixing Bath with the well buffered alkaline TF-4 (or the like) we use the fixer until advanced exhaustion of the first bath, in that case the acid from a (not suitable) Acid Stop may damage the alkaline fixer before we plan to dump it, or fixer pH may has to be corrected (with NaOH for example) to compensate that undesired Acid.
I am talking about high throughput in alkaline developer and acidic fixer. If you use a water stop for one day and an acidic stop the next day and measure the pH of the fixer at the end of each day, you will find that on the day you used an acidic stop, the pH of your fixer will be nearer to the original fix.
Well, this depends on if the Acid fixer is well formulated or not. A well formulated Acid fixer is well buffered enough to not require the acid from an Stop Bath to work perfectly until exhaustion. Still a fixer can be formulated to require/tolerate that acid intake.
You are muddying the question if you start mentioning alkaline fixer.
Man, no muddying at all. What is missleading is saying that Acid Stop protects fixer and Water Stop not. Water stop perfectly protects fixer totally because you only carry water drops with film.
If you say that some fixers require Acid addition as they are used then this can be well admited, of course, but you also may correct the pH of the fixer anyway. If one uses a not well buffered Acid fixer then he also may check pH an adding some acid, this is better than throwing an unconrolled acid amount from stop bath.
For clarity, one thing is protecting Fixer from receiving developer and another one is correcting pH.
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I don't try muddying, but clarifying.
Reality today is different than several decades ago. In the past fixers were mostly acidic... this has changed, so today we cannot say that Acid Stop protects better Fixers, we can only say that they only correct the pH of some acidic fixers as they are exausted... but Acid Stop is harmful for alkaline fixers that today are popular and increasing their popularity.
Today alkaline fixers have become increasingly popular for several reasons:
> No hypo required
> Shorter washing times
> It removes more/faster the T-MAX pink stain
> Greater capacity than acid fixers.
> Both sodium and ammonium thiosulfate are more stable in the alkaline medium of the alkaline fixer.
> Water Stop bath (clean one shot) becames a perfect solution, while classic Acid Stop is harmful, still some alkaline fixers are well buffered to resit that acid to a certain point.
> Many advantages, no disadvantage with modern emulsions not requiring a hardener that requires an acidic pH...
Also we have to remember that Acetic fumes (specially from concentrated) are a hazard in the darkroom, if wanting Acid Stop, better if using Citric.
