From: Tony McLean (tony.mclean@ntlworld.com)
Date: 04/06/02-01:18:12 PM Z
on 6/4/02 7:55 pm, shannon stoney at sstoney@pdq.net wrote:
> I have been experimenting today with developing cyanotypes in a
> solution of water and vinegar. The proportion of water to vinegar is
> five to one. But then I read that you should not mix potassium
> ferricyanide and acids, because the former might release cyanide gas!
> Does that mean it is not really safe to develop cyanotypes in vinegar
> water?
>
> --shannon
Hi Shannon,
No need to worry unduly. You would require a concentrated mineral acid to
release the cyanide from the compound, potassium ferricyanide.
Mike Ware in his book on the Cyanotype (ISBN 1 900747 07 3) expounds the
virtues of developing cyanotypes in 1% hydrochloric or nitric acid, although
this was with his revised 'new cyanotype' formula.
He extols the benefits of acid development as " a more consistent outcome,
showing a deeper maximum density and a well shaped characteristic curve,
with very long printing exposure range of about 2.4 (eight stops)".
Not sure that this would be true of the traditional formula but I would like
to hear the results of your experiments.
Cheers ..... Tony McLean.
--
If you have a moment, please have a look at my web site
http://homepage.ntlworld.com/tony.mclean/
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