Archived posting to the Leica Users Group, 2005/07/18

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Subject: [Leica] over fixed?
From: don.dory at gmail.com (Don Dory)
Date: Mon Jul 18 17:39:31 2005
References: <8FA056F3-D483-468F-B462-E05E47CCA01E@earthlink.net> <9b678e0507161922bdf1804@mail.gmail.com> <02c601c58bd6$663a82e0$2501a8c0@chartertn.net>

John,
Your experiments prove that switching to a neutral fixer is a good
thing.  The typical acidic rapid fix will in fact serve as a very mild
bleach.

Don
don.dory@gmail.com

On 7/18/05, John Black <jblack@ambio.net> wrote:
> 
> 
> > Feli,
> > You will lose the delicate almost unexposed parts of the film, or the
> > near whites if it is a print.  Without comparison you will never know
> > that they are gone.  Best to fix by time, you know the twice the time
> > it takes to clear rule.
> >
> > Don
> 
> I got concerned one time about whether I was loosing any shadows to over
> fixing and so I did a little experiment.  Since I was using neutral rapid
> fix (ammonium thiosulphate at pH 7.1), that's all I have data on.  I 
> exposed
> several rolls of Tri-X at zones I-X and developed them identically.  I then
> fixed for times ranging from 2X clearing up to 10 min.  I was surprised to
> find, after measuring the densities on a densitometer, that there was no
> loss of density in the toe of Tri-X (zones I-III) regardless of how long I
> fixed the film. I have not tried this on paper.
> 
> My clearing times with film are mostly about 25-35 seconds but I cannot
> stand to only fix for one minute so I fix as a standard practice for 3 min
> with a 3 min wash aid (mostly to help get rid of the dye).
> 
> Reasonable fixation times of 2-3 min in neutral rapid fixer will not 
> degrade
> the image shadows.
> 
> JB
> 
> 
> 
> 
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Replies: Reply from jblack at ambio.net (John Black) ([Leica] over fixed?)
In reply to: Message from don.dory at gmail.com (Don Dory) ([Leica] over fixed?)
Message from jblack at ambio.net (John Black) ([Leica] over fixed?)