[LRflex] Re: Something somewhat different
- From: David Simms <simmszee@xxxxxxxx>
- To: leicareflex@xxxxxxxxxxxxx
- Date: Sat, 5 Dec 2009 12:41:26 -0800 (PST)
Hi Charlie;
I'll study up on silver. I'm also very much of an environmentalist.
Re. washing, I pour in each change of wash water (Nikkor tank), invert it
several times, maybe let stand a bit then I allow as much to drip out as
completely as possible. I'm assuming that the agitation will
encourage sufficient diffusion of fix into each water change. If the ratio of
residual fix to fresh water added is something like 1/100, then the remaining
fix, at the end of the wash process, should be (1/100)^n where n is the number
of wash cycles. So, if I do it 10 times then (10^-2)^10 should be the
concentration at the end of the wash, or 10^(-20). Therefore, even with
imperfect assumptions about complete diffusion, archival standards should be
met. This should be good enough to last 'till the end of my days anyway and,
after that, who the hell cares ?
Cheers
Dave
________________________________
From: Charlie Falke <chfalke@xxxxxxx>
To: leicareflex@xxxxxxxxxxxxx
Sent: Sat, December 5, 2009 11:25:55 AM
Subject: [LRflex] Re: Something somewhat different
David Simms wrote:
Charlie;
>I wasn't aware that silver was particularly toxic, could you enlighten me ?
>I think that I've seen reference to silver recovery technology at places like
>the Photographers' Formulary which can be accessed online.
>
>Dave
>David,
It's in the same category as lead, mercury and cadmium,
but so are copper and zinc. Almost everything is toxic at
some exposure time and dose. In the environmental movement
in the 70s it was thought of as similar to mercury if not worse.
There is almost no data to support or refute this, possibly
because it's a less abundant industrial pollutant because it's
expensive. On the other hand huge numbers of Aerospace processes
are being revised to eliminate Cadmium, which is being replaced
largely by
At very low concentrations silver is safe and is used as a
biocide. This has been known for hundreds of years. There is
about 1ppm in Astronauts' drinking water.
Some quacks on the Internet have been pushing it as a cure all
at much higher doses, and there's plenty of data that this has
nasty side effects, including turning blue. For myself
I like to avoid becoming data if I can. I should maybe just do
silver recovery and not worry about it, but that doesn't get it all,
and the groundwater here as it is is quite clean.
It's been rural forever and we're a thousand feet above sea level,
and I'd hate to knowingly ruin that and poison myself in the process.
Referring to your wash technique, do you circulate each
batch of fresh water through a washer, or let it stand between
changes of water?
--
Charlie Falke _____ /\
| __/\__/------/__)
|(____\/_________/
"One test result is worth | |/ `o
one thousand expert opinions" - Wernher Von Braun 0 N4003M
"Imagination is more important than knowledge" - Albert Einstein------
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