From: Judy Seigel (jseigel@panix.com)
Date: 12/12/00-01:14:22 PM Z
On Tue, 12 Dec 2000, Mac Legrandi wrote:
> Hello!
>
> I went through my photo chemistry box the other day and found that I
> had some ferric Ammonium citrate which once was composed of crystals
> is now a solid deep green/blue mass. Pliable like some type of candy.
>
> Is this still usable? Can it be made soluble in water again? how? heat?
>
> I'd hate to waste this stuff.
I'm waiting for chemist to answer this question (Sil?), but I'd guess that
it depends on how MUCH blue with the green. I'd assume that the blue means
it's turned into prussian blue, which is the developed state of cyanotype,
and not necessarily reversible by water. As Sam says, the stuff is very
soluble, and should re-dissolve. But how will it print?
Mike Ware said additives ("oxidizers," as I recall, in particular the
dichromates) will repair emulsion with blue precipitate, & perhaps the dry
fe am cit as well, but my own experience is the print is very compromised
(as described P-F #5). Scale and exposure also change. Considering cost of
your time, paper, etc., it may be economical in long run to toss out the
chemical. (And, consisting of iron, ammonia, and citrate, not I believe a
hazardous waste.)
Suggestion: redissolve, & check color of the solution. If it's quite blue,
that's a warning flag. If it's green, go ahead (!). But check again when
you combine with the potassium ferricyanide -- if big blue precipitate
forms at that point, odds against you increase.
Judy
.................................................................
| Judy Seigel, Editor >
| World Journal of Post-Factory Photography > "HOW-TO and WHY"
| info@post-factory.org >
| <http://rmp.opusis.com/postfactory/postfactory.html>
.................................................................
This archive was generated by hypermail 2b30 : 01/03/01-03:59:41 PM Z CST