[pure-silver] Re: POTASSIUM -Vs- SODIUM...
- From: Lloyd Erlick <lloyd@xxxxxxxxxxxx>
- To: pure-silver@xxxxxxxxxxxxx
- Date: Sat, 03 Sep 2005 10:40:18 -0400
At 11:26 AM 9/2/2005 , Richard Knoppow wrote:
...
>Potassium carbonate is desiquescent and not as stable as
>sodium carbonate in storage.
...
> Supposedly warm tone paper developers are slightly warmer
>when mixed with Potassium salts. I've seen no actual
>evidence of this.
September 3, 2005, from Lloyd Erlick,
I bought a quantity of potassium carbonate anhydrous in 1998. I also bought
some sodium carbonate anhydrous at the same time. Actually, the sodium
carbonate was far too large a quantity (a hundred pounds) but it was such a
good deal I couldn't pass it by.
I've kept the potassium carbonate in a tightly sealed plastic container,
and it still runs freely when I open it. I also keep a small sealed
container for everyday use (I use potassium carbonate in my print developer
in place of the sodium salt) and it stays dry and free flowing there as
well. Potassium carbonate is easy to store, as long as it is kept away from
air and humidity.
My usual print developer is the old Ansco 120 formula. It's very much like
D-23; the only developing agent in it is Metol. The regular formula
specifies sodium salts (carbonate and sulfite). I heard discussion about
substituting potassium salts for sodium in developers where warm tone is
desired, and tried it. The results are definitely warmer with potassium
salts, but not dramatically so. The difference is subtle.
I'm pretty whimsical about things like numbered prints and editions of
prints. When I make some prints I like with my potassium-substituted
developer, I mark them "Potassium Edition". In a hundred and fifty years
there might be a researcher looking at my antique prints and unearthing
this discussion group to learn what a potassium edition is ...
regards,
--le
________________________________
Lloyd Erlick Portraits, Toronto.
voice: 416-686-0326
email: portrait@xxxxxxxxxxxx
net: www.heylloyd.com
________________________________
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