From: Liam Lawless (liam.lawless@blueyonder.co.uk)
Date: 10/15/02-12:03:55 PM Z
David, Judy, etc.,
I'd meant to discuss this point with Judy, but hadn't got round to it.
Fishing around for possible reasons for *staining* with cyanotype, I
remembered what had happened on (probably) cheap cardboard, and acidity
struck me as a likely cause. If acid paper was precipitating Prussian blue,
it seemed reasonable to suppose that adding acid to the sensitiser would do
the same; I'm not allowed strong acids upstairs, so just grabbed something
that was handy (i.e. tartaric).
I'm certainly no expert on cyanotype and have no great interest in the
process, and just reported what I saw, thinking someone who cares might pick
up this line of enquiry. However, I've now added more acids to cyanotype
sensitiser. Hydrochloric, sulphuric, acetic, tartaric and citric, AND alum
all turn the solution blue, more or less according to their strength. If
only slightly (as with, say, a little citric), you'd probably still get an
image, though I'd expect degraded.
Maybe irrelevant to the present enquiry, but try if you don't believe.
Buffered paper may be bad, but seems that acid would be, also. And yes,
alum is acidic.
Liam
-----Original Message-----
From: David Eastman [mailto:clearemulsions@yahoo.com]
Sent: 15 October 2002 06:17
To: alt-photo-process-l@sask.usask.ca
Subject: RE: Problem with cyanotype: Laim...Judy?
Judy-
The reason I did not ask if Laim made a boo boo was
because I don't think he did. I tend to think Laim is
right in suggesting that acid in the system promotes
the reaction and causes instaneous blueing.
On the other hand, I am not sure, because, as you
eagerly echoed my own admission, I do not make
cyanotypes.
It was and is my sole desire to ELICIT CLARICATION of
a point which, even as I stand on my head, cross my
eyes and look at this in a mirror, still seems to be a
discrepency between two very knowledgeable people; one
rather quiet, and the other, well, less so.
OK?
It seems to me that perhaps there is more than one
process being discussed here...Image Formation and
Image Preservation.
Perhaps your "Cyano doesn't like alkali. Acid is
OK." was a bit anemic.
We are all here to learn, right?
Please don't take it personal.
Ray
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