[pure-silver] Re: Chemists: WHY Is It 28%
- From: Bill <billtech@xxxxxxxxxxx>
- To: pure-silver@xxxxxxxxxxxxx
- Date: Mon, 27 Oct 2014 17:41:25 -0400
Am I just lucky? I started out with Tri-Chem packs, but once I went to larger
quantities and more variety, I started buying glacial acetic acid by the
gallon. I think the price of a quart of Kodak’s 28% had an influence. I did wet
processing for over 50 years (sadly, no longer) and in that time I had only one
problem with glacial acetic - and that wasn’t at home.
When I worked in a portrait studio’s lab, hand-developing prints, I had to keep
my chemicals fresh and that sometimes involved a trip to the loading dock,
stainless steel pitcher in hand, to pump a quart of glacial from the 55 gallon
drum stored there. Not a problem…until someone was coming out of the light-trap
curtains as I was carrying the acid in.
In case anyone is doing research, I believe it took a good-quality commercial
air handling system almost three hours to refresh the atmosphere in the
darkroom so that the 15 or so people working there could return to work. No one
was hurt, but that odor is *strong*! (They installed a buzzer with pushbuttons
both inside and outside the light trap - no further problems.)
Anyway, I think I still have a half-gallon of the stuff sitting around the
basement somewhere, since I always forget about it on hazardous waste
collection days. I wonder how much money I saved over the years…probably a
couple of dollars...
-Bill
On Oct 27, 2014, at 4:02 PM, titrisol (Redacted sender "titrisol@xxxxxxxxx" for
DMARC) <dmarc-noreply@xxxxxxxxxxxxx> wrote:
> I think it had something to do with making acid fixer solutions, acetic acid
> may decompose the thiosulphate unless it is diluted; and maybe 28% was a
> magical number to avoid that
>
> Not many people would like to have glacial acetic acid (99.xxx%) around
> knowing it can burn you
>
>
> From: Ham Burger <dmarc-noreply-outsider@xxxxxxxxxxxxx>
> To: Pure-Silver Mailing List <pure-silver@xxxxxxxxxxxxx>
> Sent: Sunday, October 26, 2014 11:57 AM
> Subject: [pure-silver] Chemists: WHY Is It 28%
>
> Since the beginning of time as a photographer, I've used the advised 1.5oz of
> 28% Acetic Acid per
> quart of working stop bath. Now, I realize this is not a super critical
> thing,
> it just has to
> stop any further development, but I am curious: Who came up with this exact
> formulation, and more
> importantly, *why* is this particular dilution right?
>
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