Stopbath - further to below

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I just read people saying no stop bath. I was using Tri-X with Kodak indicator Stop bath. Got pinholes. Kodak said dilute it down. So I 1/2'd the dilution. Now I'm getting the pinholes again and on HP5 (FP5? 400any way). So I've now WAY diluted it. Since I'm just using coloured water now, if I just use a water bath, will I be breathing in some deadly chemicals when the negative hits the fixer? I do tray processing so I can't help but breathe the stuff.

Thanks

Dean

-- Dean Lastoria (dvlastor@sfu.ca), May 04, 2000

Answers

No.

If you wanted to kill your fixer quickly, you could even go directly from developer to fixer.

-- Terry Carraway (TCarraway@compuserve.com), May 04, 2000.


Your pinholes are being caused by the sudden transition from the very alkaline developer to the very acitic stop bath. If you will use a water rinse immediately after the developer and before the stop bath, you should be able to eliminate the pinholes. I have made this a standard part of my developing procedure for many years now. It is possible to eliminate the stop bath altogether, but it will reduce the life of your fixer, so I don't recommend it.

-- Ed Buffaloe (edbuffaloe@unblinkingeye.com), May 04, 2000.

I always use a stop bath and I've never had pinholes in any film. I don't use commercially bought stop bath though, just 10ml of glacial acetic acid to a litre of water. Perhaps the problem only occurs with higher developer temperatures; I've noticed quite a few posts on this forum talking about developer temperatures of 75 Farenheit and above. 68 degrees has always been the standard as long as I can remember, and I always develop at that temperature.

Potassium Metabisulphite at 10 grams to the litre would make a milder stop bath. It's the chemical most commonly used to acidify fixing baths, so it shouldn't give any problem.

-- Pete Andrews (p.l.andrews@bham.ac.uk), May 04, 2000.


I have never used an acid stop for film, preferring an intermediate wash. However, pinholes sound very much like the bath was improperly used. They are presumably caused by the acid reacting with developer alkali (such as soda), liberating gas (CO2). If this happens at a rate too fast to allow diffusion of the gas out of the emulsion, small bubbles may result, which then look like pinholes. Correctly mixed stop is indeed not much more than coloured water, its concentration typically being 5% or even less. Consider that you don't want to positively acidify the film but to neutralise the alkali in the emulsion. Not much acid is needed to accomplish this.

-- Thomas Wollstein (thomas_wollstein@web.de), May 04, 2000.

If I may be so bold as to point out again, 1 oz. of white vinegar to 15 oz. water is a very mild stop, and I have used it at temps of 85+ degrees here in the desert. Regards, Pat

-- pat j. krentz (krentz@cci-29palms.com), May 04, 2000.


What developer are you using?

-- John Hicks (jbh@magicnet.net), May 04, 2000.

Ilfosol S. Wich is supposed to be idiot proof I heard -- But I'm thinking of trying DDX

Thanks for the advise so far. Dean

-- Dean Lastoria (dvlastor@sfu.ca), May 04, 2000.


Going off-topic but...

My experience with Ilfosol S (over many years) is that I always needed more development than recomended (for my enlarger setup), my personal EI for FP4 was about 80 and once the bottle was open it didn't last long! Once Ilfosol starts to change colour it's dead... Caught me out once, thankfully on nothing important!

I changed to Ilford Plus (LC29) and was much happier. I believe my EI is up around the stated 125, I develop for less than the recommended (pretty sure of this) and it keeps in an opened bottle much better.

However, after reading many nice comments about DD- X, I've bought some of that and are doing some tests. Too early to form any conclusions though (and I've been reading the PMK threads with interest!)

-- Nigel Smith (nlandgl@eisa.net.au), May 04, 2000.


How about using a teaspoon of citric acid in a litre water as stop bath? Has anyone heard of the citric acid type of stop bath?

-- Patric (jenspatric@mail.bip.net), May 04, 2000.

I don't see any objection to Citric Acid. In fact almost any mild acid could be used as long as it doesn't have a hardening or solvent effect on the emulsion or throw a sediment. Citric, Boric, Tartaric, even very dilute Hydrochloric should all be suitable. I bet even wine maker's anti-oxidant tablets would work.

-- Pete Andrews (p.l.andrews@bham.ac.uk), May 05, 2000.


AFAIK, Citric acid is the base for most of the odourless fixers. I wouldn't recommend hydrochloric acid, as it's too strong. This means that slight overdoses may be fatal. Besides, it's much more difficult to handle and much more dangerous than citric acid. If I recall this correctly from my chemistry lessons, there is even another problem with strong acids: Strong acids tend to give a step-like change in pH. The pH of the stop - and therefore that of the treated film - is either very acid (if there was a little too much acid) or very alkaline (if there was too little). (It's a bit like with graphical films: They are either black or white, but never gray.) Weak acids, otoh, have a smoother titration curve. This means that a little too much alkali or a little too much acid doesn't make so dramatic a difference in pH.

-- Thomas Wollstein (thomas_wollstein@web.de), May 05, 2000.

OK, scratch the Hydrochloric if you're going to drink it as well. How about Pepsi? That's got a fair amount of Phosphoric acid in it. ;^)

-- Pete Andrews (p.l.andrews@bham.ac.uk), May 05, 2000.

Typically inorganic acids will be too strong in this use. These include the hydrochloric, sulfuric, etc. Acetic acid and citric acid are organic acids and tend to be "milder". They are also somewhat self buffering (Thomas pointed out the results of this).

Citric acid is used by many since it has a much milder odor. YOu could even use ascorbi acid (Vitamin C) but the cost is somewhat prohibative.

-- Terry Carraway (TCarraway@compuserve.com), May 05, 2000.


Thanks for all your answers. You guys are way more helpful than some (most...all) manufacturer's Q answerers. I'll keep my present roughly 1/150 of Kodak Stop bath and add the tray of water between the Developer and Stop. If that doesn't work I'll try vinegar (Balsamic and I don't need to tone!). And I went out and bought fresh Ilfosol. Thanks

Dean

-- Dean Lastoria (dvlastor@sfu.ca), May 05, 2000.


Dean,

Don't use vinegar, it is the same as Kodak Stop Bath, but the concentration is not controlled. So you will never know exactly what mix to use.

-- Terry Carraway (TCarraway@compuserve.com), May 07, 2000.



Tray? You're developing sheet film? If so, I'll bet the spots that look like pinholes are actually caused by dust on the film when it's exposed.

Take a sheet straight out of the box, expose it to light and process it and see if you get the same thing. That'll give you the answer.

I really can't imagine ordinary stop after Ilfosol-S causing pinholes with HP5+.

-- John Hicks (jbh@magicnet.net), May 07, 2000.


Eliminate the stop and use water before the fix. With film you can track how your fixer is doing by keeping an eye on clearing times and fix for twice the clearing time.

-- Gene Crumpler (nikonguy@worldnet.att.net), May 08, 2000.

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