Archived posting to the Leica Users Group, 2005/11/23

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Subject: [Leica] Ups and downs of stop baths?
From: jblack at ambio.net (John Black)
Date: Wed Nov 23 08:23:17 2005
References: <BFA9C7BD.1F2B5%mark@rabinergroup.com>



> I've been up and down and in and out on stop baths. Back and forth.
> I stopped because it seem for awhile that all the real hard core darkroom
> people had stopped using it for all these various reasons. Pinholes. The
> shock of the acid making more grain. Or grain clumping.

I think there is something to that...  Any time you can keep the chemical or
physical conditions (pH, ionic strength, temperature) as constant as
possible, the image benefits.


 On and on.
> They only thing I figured out different was my fixer (HYPO) lasts a heck
of
> a longer time when I use stop bath. Really conks out faster when I don't.

I use Ryuji Suzuki's neutral rapid fixer which is NH4 thiosulfate in
sulfite/metabisulfite solution (pH 7.0-7.1). I have never had the fixer
itself conk out (ability to clear film in less than 40 seconds) but the
sulfite/metabisulfite oxidizes to sulfate rapidly (carried over developer
has nothing to do with this) and it won't facilitate the removal of the
@#$%^ antihalation dye from 35mm film as efeciently as fresh.  Tri-X and
TMX/TMY are the worst and need fresh sulfite and lots of washing to
decolorize.

I usually make fresh fixer every two sessions anyway, or use a
sulfite/metabisulfite wash aid.


> This is part of general information I'm surprised no one said that yet.
> Everything but!
> I never got a pin hole in my life.
> And that a thing I would never lie about.

You will probably not get pinholes if you don't use sodium carbonate
accellerated developers.  They produce CO2 gas when combined with acid,
sometimes, such as acetic acid stop or fixer.  Borate buffered developers
don't do this.  Old time D76, I think, used to have sodium carbonate in it
but has been reformulated to use borax/boric acid or metaborate I think.  No
gas.  Take Tums and you won't get pinholes!

JB



Replies: Reply from ericm at pobox.com (Eric) ([Leica] Ups and downs of stop baths?)
In reply to: Message from mark at rabinergroup.com (Mark Rabiner) ([Leica] Ups and downs of stop baths?)