On Thu, 16 Dec 1999, stan johnson wrote:
> This would be the same as about 6 grams of Se in 1000mL (1 liter, 1L)
> of solution. [Ignoring the volume contributed by the dissolved solids,
> which would be a reasonably minor correction.] Thus 5 grams per L is
> actually less than Judy's proportion, or at least not significantly
> different.
You know not every great artist can multiply and divide while on line...
so apparently the difference between the 2 formulas is less than I
thought, in which case there is or is not another explanation.
I double checked my original file cards, and copied correctly, and the
selenium did dissolve. Which leaves room to speculate that the form of
selenium I used was more soluble in water... Or, name your theory.
My formulas are both marked "Kodak", I have a dim memory that I found them
in some brochure of the 40s, but again that was 20 years ago and the
experience wasn't traumatic enough to have imprinted itself on memory.
Incidentally the "flask" I used was a spare bottom from a Melita drip
coffee maker, it's Pyrex, so could be put directly on stove, and also had
narrow neck. Now that Melita is replaced by something trendier (the kind
you squoosh the grinds into that a close relative clogged drain with the
grounds from because it doesn't use a filter), you should get the melita
thing cheap at the thrift shop. Sorry I don't have the exact technical
terms here. I'm not a coffee drinker. As for the lecture about possibly
poisoning someone who comes to my darkroom and gulps selenium out of the
melita bottom... oh, well, thanks in advance.
And PS to Tan: Both these formulas are quite different from KRS, and for
the paper I was using, much more beautiful. On old Brovira, KRS gave no
color shift at all -- which was why I started with the formulas. They
also don't have added fixer so (it seemed to me) the same kind of archival
washing wasn't necessary. I put the already washed and dried prints into
toner... never toned directly from the fixer, for many reasons, including
the fact that by the time I washed the print it had usually had 24 hours
in holding bath and emulsion was ready to slide off the paper, and so was
I.
Best,
Judy
> On another point, an earlier note in the thread mentioned a recipe by
> Clerc, "Sodium selenosulphate may be obtained by dissolving 260 gr. of
> powdered selenium in 20 oz. (30 grm. in 1,000 c.c.) of a warm 20 per
> cent solution of anhydrous sodium sulphite."
>
> I suspect that Clerc was specifying the use of 260 grains, not 260
> grams. 260 gr. [grains] = 16.9 g [grams] approximately. 20 oz. of solution
> = 1.18 L approximately, for a proportion of about 16 g/L. About three
> times Judy's recipe's proportions. Doubtless the amount of sulfite etc.
> will influence the amount that will react/dissolve.
>
> stan
>
> --
> Stan Johnson
> sjohnson@gwi.net
> 12/16/99 12:40am
>
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