RE: Cyanotype Problem

From: Keith Gerling (kgerling@ameritech.net)
Date: Fri Dec 03 1999 - 04:47:56 /etc/localtime


Judy,
I hesitate to admit I've never used the traditional cyanotype. I'm not
shunning the celebrities, mind you, I've just read that Ware's version
resulted in deeper blues, with less exposure, etc. I'll give the
traditional version a try in the next few weeks and report back. Tony
McClean could be right about the ph: living in the sticks, using well-water
AND with farmers who dump all kinds of high potency Nitrogen fertilizer into
the soil, God knows what kind of ph the water has. But my distilled water
bill is already too high with what I run through my espresso machine!

Keith

-----Original Message-----
From: Judy Seigel [mailto:jseigel@panix.com]
Sent: Thursday, December 02, 1999 7:11 PM
To: alt-photo-process-l@sask.usask.ca
Subject: Re: Cyanotype Problem

On Thu, 2 Dec 1999, Darlington Media Group wrote:

> Keith,
>
> The reason your cyanotype image is fading when the gelatin is applied is
> due to the nature of 'prussian blue'. This compound will fade irreversably
> in any alkaline solution, and I suspect the gelatin or
glyoxal/formaldehyde
> solutions have a pH greater than 7. You could check this out with some pH
> paper and adjust the pH of the solution to neutral. The border, being
> denser, will be the last part to fade.

This isn't so -- that is, cyanotype as undercoat for gum is a time honored
practice and many do seem to gelatin size over it, tho I personally have
not. Among celebrity artists who do gum over cyano, those who spring to
mind are Sam Wang, Teresa Van Hatten and Sarah Van Keuren who do or don't
size after the cyano, Sarah does, I do not. In fact a certain famed
publication had an article by sarah, just this past issue, in which she
describes gelatining over cyano.

My suggestion at this point would be that Keith add to the sum total of
human knowledge by doing this with same old, boring, ordinary (that is,
regular) cyanotype. There are definitely some advantages to the "new"
cyanotype, but they are essentially frills.

And PS: the "old" cyanotype is what cited celebrities use. The "new"
operates quite differently and may simply faint (in all senses of the
word) at the sight of gelatin.

Judy
.................................................................
| Judy Seigel, Editor >
| World Journal of Post-Factory Photography > "HOW-TO and WHY"
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.................................................................

>
> What effect this will have on the 'setting' properties of the gelatin is
> anybodies guess. Or, you could stick with a Pthalo blue gum as an
> underlayer and play safe. <g>
>
> Tony McLean.
>
>
>



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