Judy Seigel (jseigel@panix.com)
Mon, 18 Jan 1999 16:00:49 -0500 (EST)
On Mon, 18 Jan 1999, joel lederer wrote:
> My idea is to eliminate sol. B (ferric oxalate+K. chlorate) and replace
> it with a concentrated solution of K. chlorate and add this to the
> sensitizer with a micro pipette (I have seen ones which measure out in
> 1/100ths of a cc). The plan would be to make a solution strong enough so
> that the highest contrast could be achieved without "watering" the
> mixture down too much and not so strong that I loose the ability to
> measure small amounts when a slight increase in contrast is needed.
> Ultimately I would like to use a solution in which 1/10th of a cc would
> be the highest contrast (for a 4x5 print) and 1/100th of a cc would be
> the lowest contrast. For larger prints the amount could be multiplied.
> I'm not sure where to begin with these experiments and have thought of
> some questions. Perhaps I'm missing something obvious.., but here goes.
Joel, I don't know any of the fine points of pl/pd (or the medium points
either, for that matter). But it seems to me what you're suggesting is
very much like the method Alan Newman devised & taught 20 years ago &
which was the way I was taught, a method which has always seemed to me
more convenient than the "traditional."
I don't recall the k chlorate concentration, but you mixed it up
separately (probably 15%, I'll look it up if no one else has it) and add
by drops to your mix at mixing time. It has the great advantage also in
that for a very small amount you can cut a drop with a drop of distilled
water before adding. The straight K chlorate certainly kept for the
period during which I used it.... say 6 months ... and I daresay keeps
still in the back of a shelf somewhere...
cheers,
Judy
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