From: Liam Lawless (liam.lawless@blueyonder.co.uk)
Date: 10/12/02-07:49:43 PM Z
Richard,
What do your chemicals look like - like they did when you bought them? And
are they old; did they work OK before? If I had to hazard a guess, I'd go
for the ferricyanide being off. With long exposure to air, it starts to
look dirty. Badly affected, it goes green on the surface, but with less
exposure the orange crystals just lose some of their brilliance. The usual
problem with f.a. citrate (if you have it as the very fine powder) is
absorption of atmospheric moisure, turning it sticky at first and eventually
into a solid lump. Apart from that, I don't believe it's greatly affected
by oxygen (though I could be wrong).
But if you're getting blue on mixing the solutions, I'd also say there's a
good chance of contamination. Could either of your bottles have been less
than perfectly clean? Another possibility: rust. Rust (from, e.g., a
corroded spoon) will instantly form blue in a ferricyanide solution, but if
in with the f.a. citrate, not until the two are mixed.
Liam
-----Original Message-----
From: Richard Urmonas [mailto:rurmonas@senet.com.au]
Sent: 13 October 2002 02:18
To: alt-photo-process-l@sask.usask.ca
Subject: Re: Problem with cyanotype
On 2002.10.13 02:00 Liam Lawless wrote:
Liam,
Thank you for the reply.
> Two things to look at. If you're getting a blue solution, it's
> probably the
> condition of the chemicals
I suspect it is bad ferric amm. citrate. I was hoping that there was a
mistake
on my part, but after more tests it looks more and more like the
citrate.
> But your paper just might be unsuitable.
I had already tried two different papers, but as a further test I mixed
a little
of each solution on a clean dry piece of glass. Still a rapid
appearance of blue
when they mixed.
Does anyone know of a method to "purify" ferric ammonium citrate ?
I don't really want to have to buy a new batch (from a different
supplier).
Thank you,
Richard
--- Richard Urmonas rurmonas@senet.com.au
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