[pure-silver] fixer composition (was Re: Re: PMK)
- From: Ryuji Suzuki <rs@xxxxxxxxxxxxxxx>
- To: pure-silver@xxxxxxxxxxxxx
- Date: Thu, 27 Apr 2006 23:07:57 -0400 (EDT)
If this is of interest to you, you are recommended to read original
research reports from early 1970s. There are two important researches
in this area. One is by Green and Levenson of Kodak Harrow Lab, and
another by Aelterman and Vanreusel of AGFA-Gegaert Lab in Mortsel,
Belgium.
Green and Levenson also did a series of studies about washing
properties, etc.
From practical viewpoint, you want to use non-hardening fixer of pH
well above 5, preferrably in the range from 6.5 to 8.5. It's also very
important to give sufficient fixing time (2x to 3x the clearing time)
because material fixed just to clear will require MUCH longer washing
time to remove harmful fixing reaction products. Ammonium thiosulfate
fixers fix and wash faster than sodium thiosulfate fixers, but the
ammonium salt based fixers may be undesirable in the sewage effluence
in some areas due to high content of ammonia, a biologically useful
nitrogen source.
For small tank development, stop bath is unnecessary. I use water
rinse and it is totally adequate. However, if you prefer, you can use
a dilute acetic acid stop bath, or a buffered acid stop bath.
There are some advantages to well formulated neutral to weakly
alkaline fixers, but I must say some of the popular advocates of this
topic are misleading. You would be happier without reading more about
it, unless you are willing to get those papers by Levenson, Green,
Aelterman and Vanreusel.
From: "Hagner, Andrew" <Andrew_Hagner@xxxxxxxxxx>
Subject: [pure-silver] Re: PMK
Date: Thu, 27 Apr 2006 18:58:53 -0400
> All my life I have been using the standard alkaline/acidic process. Can
> you describe the steps? How is the development arrested without a stop
> bath or perhaps it is not needed. What is used as a fixer, just pure
> sodium thiosulphate? Better yet, are there any references to read that
> deal with the process?
>
> - Andrew.
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