Re: VanDyke Precipitate
S_IZZO@guvax.acc.georgetown.edu
Sun, 07 Sep 1997 13:35:48 -0400 (EDT)
Mac Cosgroves-Davies wrote about getting a white precipitate when
mixing a new batch of VanDyke sensitizer.
I had a similar problem a few months ago: upon adding the silver
nitrate solution to the mixture, it seemed to curddle. I too was
using new ferric ammonium citrate. However, mine was from Bostick
and Sullivan. I was also using the formula from Keepers of Light.
I went ahead and used the sensitizer, shaking it up well each
time just before using. I seemed to work all right. (I also let
the precipate settle and used the clear liquid on top, and that
also seemed to work.)
Strangely enough, two days ago I mixed up another batch of VD
sensitizer, expecting the same results (same chemicals and formula).
This time there was no curddling.
I can't explain any of this. My suggestion is to try what you
have mixed up. If the results are not satisfactory, try mixing a
new batch.
Good luck. Suzanne