Re: Reversal processing for enlarged negatives

On Fri, 26 Mar 2004, Ryuji Suzuki wrote:

> > effects of very small amounts. in fact i was so surprised i asked the
> > chem prof at school -- how could 1 drop of a 20% solution in a liter,
> > etc. etc.... his explanation was, my dear, there are billions of ions in
> > everything. (though maybe he only said millions.)
>
> that professor needs a shot of whiskey before saying such a trivial thing...

Some folks can say trivial things even without a shot of whiskey, but this
remark was exactly right under the circumstances, its tone also assuring
me that it could actually happen, which was what I needed, not a
scientific explanation which would have required about a month of analysis
& then been irrelevant.

The fellow was extremely supportive in other ways, too, getting and
lending obscure chemicals and equipment (also brillinat, had a couple of
patents, etc.) But maybe you had to be there...

> by the way, copper sulfate is another toxic chemical. i wouldn't want
> ot use it for a bleach unless there is absolutely no alternative.

The Health Hazards book which can get alarmist about gum arabic says
"slightly hazardous by skin contact and moderately toxic by inhalation or
by ingestion," which in the toxic scale of that opus is next to zero.
It's sold freely for garden use and comes without warnings with the
Halochrome kit, and in the scale of what I was working with (lead, silver,
acids, etc. etc.) was on the mild side. All my plating formulas (or 9
out of 10) required it. But alternatives were scarcely better... Potassium
ferricyanide is called "slightly toxic"... also not recommended for
munching.

But I NEVER get ANY chemicals on my extremely allergic skin -- in the wet
darkroom I wore gloves even to pick up tongs --- and with one other
practice, which I share -- seemed to survive many hours & many gallons;
I did not EVER leave a tray of anything but water uncovered... Had plastic
covered cardboard to fit every tray. And lifted those covers only to put
something in or out (except for brush developing, which took 3 min. of
open tray). This made an enormous difference, and better IMO than
counter-level exhaust, which still pulls current into the air. You still
smell it.

Judy
Received on Fri Mar 26 22:35:32 2004