[pure-silver] Re: DELTA 100 AS REPLACEMENT FOR Tmax 100
- From: "BOB KISS" <bobkiss@xxxxxxxxxxxxx>
- To: <pure-silver@xxxxxxxxxxxxx>
- Date: Wed, 9 May 2007 12:06:56 -0400
DEAR RICHARD,
For current wisdom your MSDS trumps my local chemist but I will
continue to use standard precautions (gloves, minimize chem dust, etc.) with
phenol based dev agents, toners, most alt photo chem, and processing in
general for the following reason:
In the Toxicity section of the Appendix on page 58 of Gordon
Hutchins "BOOK OF PYRO", he cites, among other things, ease of bodily
absorption, toxicity, and "...the debilitating effects of kidney
dysfunction...". On page 59 he states that pyro easily crosses the
blood-brain barrier and causes "variance in blood pressure, somnulance
(sleepiness and lethargy) and convulsant activity (Wylie and Archer, 1960;
Angel and Rogers, 1972; Tache and Tache, 1977)"
In the next sentence he states, "Laboratory research indicates that
pyrogallol and its primary oxidized form, purpurogallin, are probably
mutogenic and carcinogenic agents (Ben-Gurion, 1979; Van Duuren, 1980)."
I repeat that I have used PMK for 10 years and intend to also use
other variations of pyro formulae so I sincerely don't want to discourage
anyone from trying/using staining developers. Gordon's info simply
reinforces my dedication to simple, standard, lab/darkroom safety practices:
Gloves at all times, respirator when mixing, goggles with certain other
chems. Reasonable darkroom safety is a situation where "more is more".
*****I recommend Gordon's book as required reading for anyone who wants to
try pyro.
CHEERS!
BOB
-----Original Message-----
From: pure-silver-bounce@xxxxxxxxxxxxx
[mailto:pure-silver-bounce@xxxxxxxxxxxxx] On Behalf Of Richard Knoppow
Sent: Wednesday, May 09, 2007 11:19 AM
To: pure-silver@xxxxxxxxxxxxx
Subject: [pure-silver] Re: DELTA 100 AS REPLACEMENT FOR Tmax 100
----- Original Message -----
From: "BOB KISS" <bobkiss@xxxxxxxxxxxxx>
To: <pure-silver@xxxxxxxxxxxxx>
Sent: Wednesday, May 09, 2007 6:42 AM
Subject: [pure-silver] Re: DELTA 100 AS REPLACEMENT FOR Tmax
100
> The info I received from a chemist at our Barbados
> National Standards
> Institute was that pyrogallol was both toxic and
> carcinogenic, i.e, in large
> doses it will make you very sick (if not dead) and in
> small repeated doses
> it will give you cancer as it builds up in your liver.
> Now, that being said, I have used PMK for 10 years. I
> just mix it using my
> respirator (and keeping dusting to a minimum) and gloves.
> I wear gloves when
> ever developing film, whether I am using pyro or not.
> With standard simple
> chem lab/darkroom precautions there should be no problem.
> However, do NOT
> treat pyro as not dangerous once in developer
> concentrations because the
> repeated exposure to the small amounts that would
> penetrate your skin
> without gloves could eventually cause cancer. Why risk it
> when it is so
> easily avoided.
> CHEERS!
> BOB
I've looked at a number of MSDS for Pyrogallol and can
find none which list it as a carcinogen or suspected
carcinogen.
It is toxic in fairly large quantities and can cause
problems as both an acute and chronic toxin. It is a strong
skin sensitizer and can cause respiratory problems if
breathed in. Liver and kidney problems can be caused by
ingestion but the most serious problems seem to be from
chronic ingestion.
Pyro usually comes in fine flaky crystals that become
airborne easily. It should be handeled with care to prevent
it from getting into the air and a dust mask and eye
protection should be worn.
Pyrogallic acid was originally derived from nutgalls, a
an exudation on trees (frequently Oak trees) caused by
irritation from the larvae of an insect related to the
Aphid. It is now made by synthesis.
Pyro is a member of the Phenol developing agents, related
to Hydroquinone.
One practical problem with Pyro is that it causes stains
on skin and fingernails. These are typically brown and very
hard to remove. At one time Pyro was used as a hair colorant
for humans and for dying fur. Its toxicity has eliminated it
from these applications.
Pyro as a photographic developer was discovered by
Fredric Scott Archer c.1865, it was very widely used until
the late 1920's when Metol and Hydroquinone developers
pretty much supplanted it.
---
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx
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