Re: [Leica] Re: B&W revisited

[Kip Babington <cbabing3@swbell.net>]

RBedw51767@aol.com wrote:
> 
> George:
> 
> Thanks for your input.  I wasn't aware that PYRO is as toxic as you stated.
> When I use it I will definitely use gloves. . . .

I made a comment earlier in this thread that gloves weren't necessary
with the mixed developer in tanks, and I don't want people to get the
wrong idea about that comment.  Hutchings has four pages, in one of the
appendices to his Book of Pyro, about the toxicity of Pyro and
precautions for use, but it is clear that the hazard is primarily with
handling and mixing the powdered form of pyrogallol, and with long term
submersion of the hands in the mixed PMK developer.  Pyro dust and gases
released in mixing stock solutions from powder apparently are the most
serious hazards.  And he says that when he has developed sheet film in
trays without using gloves he can begin to taste the effects of the
developer within 60 seconds of first putting his hands in the stuff, the
body absorbs it that fast.

But Hutchings adds the following:  "For most non-tray film processing,
there is no need for the gloves.  A drop or two of the developer on the
hands is relatively harmless.  All tank, reel and nitrogen burst systems
may be operated without gloves."  And if you use the Liquid PMK kit from
Photographers' Formulary (others may offer one too) there is no powder
to handle and mix and so no gas to deal with before you get to the
working developer.

For those concerned about the environmental impact of disposing of PMK
after use, he adds that "Pyro is a water soluble organic compound. 
Every indication is that it oxidizes and breaks down almost immediately
and therefore should pose no special disposal problems.  The pyro from
my darkroom has drained into a septic tank for 14 years.  Even though
pyro is a bactericide, no problems have occurred."

Hutchings does warn, of course, that each user must make an individual
judgment about an acceptable level of exposure.  But I have determined
that, at least for me, mixing working developer from liquid stock
solutions (using syringes with long pickup tubes (available from
Formulary) to retrieve and measure the stock) and using Paterson tanks
does not require the use of gloves when developing Leica negatives
(there - back on topic.)  If a drop or two of developer leaks out of the
tank during agitation, I just rinse it off.  Make your own judgment in
your own circumstances, but it is not necessarily reckless to dispense
with the gloves when using PMK.

Cheers,
Kip