Just back from holiday.
I don't want to re-open the previous thread, but just to pick up one point
in it that could be dangerously misleading:
> But I remember Peter telling me that when he worked
> in industry he handled potassium cyanide without gloves and that that was
>OK so long as one washed one's hands.
The term HANDLING should NOT be taken to mean touching with the fingers. We
handled cyanides (and many more toxic materials) with a spatula, taking
pains to avoid any contact with skin.
Washing hands after all chemical 'handling' procedures is simply good
practice. When handling cyanides we always had the two labelled bottles of
cyanide antidote at hand (though legend was that their use caused more
medical problems than the cyanide itself.)
When I worked with dyestuffs, the company I worked for had once been
associated with Perkin, the founder of the synthetic dyestuffs industry, and
some of our sample bottles still had his signature on them. Legend has it
that he made a point of working in the lab 'handling' these most intensively
coloured substances in his suit with no lab coat, gloves or other protective
clothing as he considered the good chemist could avoid all contact with the
materials he was handling.
Bill Jay has written somewhere of the many fatal accidents to photographers
when cyanide was used as fixer.
As always the message with materials is to know the hazards involved and
take suitable precautions.
Peter Marshall
On Fixing Shadows, Dragonfire and elsewhere:
http://faraday.clas.virginia.edu/cgi-uva/cgiwrap/~ds8s/Niepce/peter-m.cgi
Family Pictures & Gay Pride: http://www.dragonfire.net/~gallery/