Re: Reversal processing for enlarged negatives

From: Judy Seigel <jseigel@panix.com>
Subject: Re: Reversal processing for enlarged negatives
Date: Thu, 25 Mar 2004 22:11:34 -0500 (EST)

> i estimate that i toned about a thousand prints (maybe more -- i had
> something like 15 cases of old brovira, with 10 boxes per case, 50 sheets
> per box) so i was pretty familiar with the operation. it's quite possible
> i was using a stronger krst... this was more than 20 years ago, and only
> one or two prints, because i didn't do it again. however, if 27% of the
> stock solution is ammonium thiosulfate, i would not expect, even at 1:10
> much image potential to remain.

well, i want to do a few quick tests on this, but this is my emulsion
month and no toning is allowed during this period. ideally i want to
rent two different rooms for each purpose but i can't afford to do
that. even a thousandth of a milliliter of the stupid fixer
contaminating in to a batch of emulsion will screw it up. toner is worse.

> i also found, however,that infinitesmal
> amounts could have a very profound effect. i used to use a pre-bath of 1
> drop of a 20% solution of a sulfide mix in a liter of water for 30 seconds
> before bleaching and it gave a distinctly different effect... it's
> probably a mistake to even mention, because i don't remember specifics and
> don't feel like looking them up... but it comes to mind a propos of the
> 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...

sulfide makes extremely insoluble and stable compound with silver, and
sulfide solution is pretty active even at very high dilution. so this is
entirely plausible, though i have no confirmation.

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.

> actually i thought the fuss about selenium poison was a lot of ado about
> very little. i was very carefully putting a small quantity in water. but
> there seem to be different forms -- mine is not powdery, but quite
> granular.

Selenium powder is classified toxic for a reason. when I handle it, I
wear a face mask on top of protective goggle, a lab coat and glove,
and only in a wel ventilated area. If I have to do this once every
week or more frequently, I need a respirator. Once the toner is mixed,
it's not as toxic, but I still wear gloves because I tone virtually
all prints I make, taking hours.

> I think it was
> Sil Horwitz who pointed out that we require trace elements in our diet,
> maybe to keep our fingernails from breaking, and people take selenium
> pills if they don't have enough in their hair ! (It occurs to me to
> mention that this last is meant to be funny. Sorry if it isn't.)

Yeah selenium is in seafood, chicken, calf liver, grain germs,
etc. BUT you are supposed to take only 0.1mg per day. Suppose you
don't eat anything and drink selenium-free water, that's a ten
thousandth of selenium called for in a liter of toner. My selenium
stock is a fairly fine mesh powder, and very easy to fly around in the
air. Plus, the form of selenium in toner is very different from the
form in diet. I would rather eat an oyster instead of selenium. By the
way, excessive selenium intake can cause damage to hair, nail and
teeth.

--
Ryuji Suzuki
"All the truth in the world adds up to one big lie." (Bob Dylan 2000)