From: Judy Seigel (jseigel@panix.com)
Date: 01/24/02-10:57:52 PM Z
On Thu, 24 Jan 2002, Sandy King wrote:
> I don't understand what taping the borders will accomplish. It is my
> understanding that the stain results from ferrous metals that are
> left in the paper. Are these metals not also found in the image area
> of the print as well as the borders? If so, would not the image areas
> be degraded even if you managed to keep the border areas clean by
> taping?
Sandy, you raise an interesting question, in that I'm finding residual
iron (I assume it's that) in cyanotype. Paper looks perfectly cleared,
perfectly white, but when I did some cyano toning tests I found that a
part of the paper that was coated & masked took on more "stain" from the
toning than the part that hadn't been coated. This occurred on 3
different papers, all of which had been given MORE than the usual cyano
wash. Since I have never had a problem with cyano permanence, nor heard of
anyone who has... I dare suppose maybe it it doesn't matter.
There is a test for residual iron, involving a product called Tiron. I
have some on the shelf. Sat there so long it's probably turned to lead,
and what it tells, who knows? Science is all around us, and shibboleths
fall like ten pins. This week they're saying forget the mammograms, they
don't cut down on death from cancer. So next week they'll say don't worry
about clearing iron?
However, I'll add that the tone difference was so slight you had to look
for it, and would hardly show where there was a general range of density.
Would not "degrade" the image, especially since a touch of tone rather
enhances an image (in certain schools of thought).
> Is there any question of permanence associated with complete clearing
> of the ferrous metal from the paper? In kallitype printing, which is
> of course closely related to platinum in the way it functions, I
> understand that residual iron let in the paper is one of the major
> problems relating to permanence.
Hmmmm. This is proved? How many kallitypes are in custody to tell
that... well, we've been there before, haven't we?
Judy
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