[pure-silver] Re: WORKING OR STOCK? Darkroom Chemistry... Question
- From: "Brian Smith" <dmarc-noreply@xxxxxxxxxxxxx> (Redacted sender "smithcbrian2@xxxxxxxxx" for DMARC)
- To: "pure-silver@xxxxxxxxxxxxx" <pure-silver@xxxxxxxxxxxxx>
- Date: Wed, 4 Mar 2015 21:51:21 +0000 (UTC)
Thanks Richard. I might look up some of the old references just out of
interest. Regards - Brian
From: `Richard Knoppow <dickburk@xxxxxxxxxxxxx>
To: pure-silver@xxxxxxxxxxxxx
Sent: Wednesday, 4 March 2015 7:50 PM
Subject: [pure-silver] Re: WORKING OR STOCK? Darkroom Chemistry... Question
On 3/3/2015 1:04 PM, Brian Smith (Redacted sender smithcbrian2@xxxxxxxxx for
DMARC) wrote:
Thanks Richard for you very informative reply on fixers. Given that I don't
use a hardening agent (and ignoring any minerals in the wash water), could I
omit the EDTA from HCA without affecting its pH? Regards - Brian
I don't think the sequestering agents have much effect on the pH. They
are mainly meant to prevent sludging from aluminum compounds from the fixer and
probably magnesium from the wash water. I think they are also added so that
the wash aid can be reused. I generally use it one-shot. I posted the
citations to Kodak's technical papers and the patent long ago but would have to
search through my records to find them. BTW, Kodak did an enormous amount of
research on fixing and washing. Much of this stuff was published in more than
one place, often the Journal of the Society of Motion Picture Engineers. When
the labs were created in 1912 Meese and associates decided that their
scientific and technical papers should be published in established
peer-reviewed journals rather than in a house organ. This gave Kodak's papers
an immediate prestige they would not otherwise have had.
--
Richard Knoppow
dickburk@xxxxxxxxxxxxx
WB6KBL
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