Re: Aqua Regia & safety

About this list Date view Thread view Subject view Author view

From: Katharine Thayer (kthayer@pacifier.com)
Date: 02/21/03-02:00:39 AM Z


Hi Gord,
I need to understand why I've been getting only a few of the alt-photo
postings. I've noticed now and then posts responding to a post I didn't
see, but since I don't read every post anyway, that hasn't aroused any
particular concern. But this morning, noticing that I didn't receive the
post that Phillipe's post is in response to, I went to the archives and
found that while I have received only three posts on Aqua Regia and
Safety: your original one, Sandy King's, and this one from Phillipe
Moyer, there have been some 15 intervening posts in the thread that I
didn't receive. What could account for this?

I think the idea of a list-sponsored set of safety guidelines is a good
idea, but I also think that the people writing the information should be
knowledgeable about chemistry and how to handle chemicals. To say that
the two opposing sides on the aqua-regia issue have to draft a common
safety guideline on aqua regia is to me like putting holocaust survivors
and holocaust deniers in a room together and telling them that they have
to write a common history of WWII, and if they can't agree, then you'll
post both of their points of view as if they were equally valid.

The person who claims that he's added water to acid without any ill
effect, leading at least one reader apparently to conclude that the acid
to water rule has been discredited by his observation, is not a person I
want writing chemical guidelines for new alt-photo workers. Saying that
you've added water to acid and nothing bad happened, therefore adding
water to acid is not a problem, is like saying that because you played
Russian roulette once and didn't get the bullet, then Russian roulette
is a fine game and everyone should play it. There is a very good reason
why every beginning chemistry lab student has to memorize "acid to
water, the way we oughter" and I for one, as a list participant with
some chemistry background, would want that time-honored and tested rule
of chemistry to be respected in any guidelines that we as a list provide
for beginning alt-photo workers.

Rather than asking the two extreme positions on this issue to try to
find common ground, I think it may be better to have someone less
involved with the debate but knowledgeable about chemistry, draft a
simple guideline for aqua regia. Someone in this thread proposed a short
sensible list starting with "Use a hood...." which I can't locate in
the archives now but seems to me like a good place to start.
  

My 2cents.
Katharine Thayer

Monnoyer Philippe wrote:
>
> Judy,
>
> It's a bit hard for me to make the link between my post and your short reply. I think you interprated it beyond what I meant.
> Indeed, it would be ridiculous to consider chemicals do present the same risk with a rated scale.
> As for fattening agent though, all other conditions being equal, peanut butter will obviously win the race.
>
> This was my absolute last mail on that topic.
>
> Philippe
>
> |
> |
> |Philippe, I have worked extensively with dichromate & not with
> |aqua regia,
> |but my feeling is it's simply impossible to rate the relative danger.
> |I've read a lot of the 19th century literature about workers
> |in dichromate
> |who had hellacious agonizing skin lesions, without -- for nearly a
> |lifetime -- a clue what caused them. I am most EXTREMELY
> |allergic myself
> |(I could get hives, when I was in full bloom turpentine allergy, from
> |sitting in a chair that someone with turpentine on her hands
> |had put her
> |hands on 5 hours earlier, or using floor wax or shoe polish, which have
> |turpentine, which is, I understand one of the two most allergenic
> |substances to humans -- the other being chrome.)
> |
> |Yet, I have managed by keeping hands out of it, and other care, to use
> |dichromate for 10 years and apparently OK ... Though I've
> |found that even
> |putting bare hands in final "clear" washwater, as I occasionally did in
> |"emergency" at school, left me with discomfort in skin for a
> |day. I also
> |know that an occasional splash on bare legs of just a tiny dot
> |of the gum
> |soaking water that I didn't notice at the time, causes a burning itch
> |within an hour or so... It's quickly removed by rinse with
> |clear water --
> |but it suggests to me all sorts of ramifications of danger.
> |
> |As for the turpentine -- I shudder to think of the classroom situations
> |where each of 50 or even 20 students has an open palette with
> |turpentine
> |evaporating into the room. We had that in art school... I hadn't
> |developed the allergy at the time, but it surely was a factor. And I'll
> |add that my own turpentine allergy at one time was so severe I
> |verged on
> |anaphylactic shock.
> |
> |In other words, trying to "rate" the danger is not only moot, but not
> |necessarily useful. It could cause someone to relax where they
> |shouldn't,
> |and panic where it's also beside the point. It's like trying
> |to say which
> |is more fattening, peanut butter or steak or Courvoisier. It depends
> |where, how, how much, and who.
> |
> |As for that Hazards book, I found it absolutely useless. It
> |has no sense
> |of proportion, rating all hazards as if you were using
> |industrial strength
> |amounts for a 40 hour week. So you either discount it
> |entirely, or give up
> |at the outset.
> |
> |And to come back to the precipitating issue here, Liam's
> |formula was for
> |50 ml (less than 2 ounces !) of aqua regia, which was then
> |diluted. That's
> |about a shot glass full.
> |
> |And now, Philippe, since you seem a level-headed sort -- what do you
> |think about working with ether, gun powder and rat poison, as
> |has had NO
> |warnings on this list, not a single solitary one, although
> |wetplate is
> |the latest rave, craze, passion.
> |
> |And, would you compare the danger of splash or fumes from aqua
> |regia with
> |Dutch mordant (the strongest etch for printmakers) or nitric
> |acid, which
> |we used all day long in open trays in print making, probably
> |from 2 to 4
> |litres in a tray, probably 4 or 5 trays in a room. Nobody said a WORD
> |about danger -- it was assumed that we were adults and knew it
> |was strong
> |enough to bite metal.
> |
> |Judy
> |
> |


About this list Date view Thread view Subject view Author view

This archive was generated by hypermail 2.1.5 : 03/04/03-09:19:09 AM Z CST