From: Sarah Van Keuren (svk@steuber.com)
Date: 05/02/00-06:54:43 AM Z
Eric Neilsen wrote:
> I can understand a reluctance to get involved with chemicals if you have a
> sensitivity to them or are at risk due to exposure. I have pounds and pounds
> of oxalic acid around, I use it to make potassium oxalate and as a clearing
bath
> for platinum/palladium prints. You might also consider switching to ammonium
> ferric oxalate which is much cheaper and if you do, I would recommend that you
> buy it from Artcraft. He had the highest quality for good prices. It would
> also allow you to teach a POP method and clear with water or a little sodium
> sulfite (and EDTA tetrasodium).
>
> Are you teaching mordancage? The H2O2 could be used with that process as
> well. I posted a how to make ferric oxalate piece on my web site some time
> back. It can be accessed through
> http://e.neilsen.home.att.net/FerricOxalate.html. I could work up a "How to
> renew" but I would need some bad ferric. Do you use potassium chlorate? If
so,
> I would not renew that batch.
>
> How do you know the ferric is bad? fogged prints? or blue result with test? Do
> you add any oxalic acid to the ferric when you get it or do you buy liquid? I
> know there are a lot of questions here, but it helps me see where you are at
> with your ferric usage and how you can just save energy and money.
>
> Good luck with what ever you decide.
>
> EJ Neilsen
> --
> Eric J. Neilsen
> 4101 Commerce Street, Suite #9
> Dallas, TX 75226
> 214-827-8301
> http://e.neilsen.home.att.net
> http://www.ericneilsenphotography.com
Eric, I checked out your website: very impressive, both information and
images.
However, the description of converting the ferrous oxalate to ferric is way
beyond what I can feature doing in our busy printmaking studio at U Arts
where
I certainly couldn't leave chemicals out to settle overnight, for instance.
(I
am teaching my classes in Printmaking rather than Photography and my own
background is painting/printmaking and later on photography.) We buy liquid
A and B bottles of ferric oxalate from Bostick and Sullivan so the potassium
chlorate is in half the material to be recycled. I don't know for sure that
each
batch is bad after 6 months but go by what B & S recommends, although we
keep the
expired bottles on hand for about a year. It is not worth it to me to have
the students get tripped up with foggy prints in an introductory survey and
as an adjunct professor I don't have time to check by making a print ahead
of
time. The advanced students get to use up the older A & B if we run low.
They know
enough by then to recognize fogging. I've heard contradictory reports about
the potassium ferricyanide test ‹ some say it is overly sensitive but your
dilute version probably gets around that. In any case, my students make good
and often very beautiful palladium prints most of the time with our
arrangement.
I must tell you that my personal commitment is to cyanotype and gum. This
will explain why I am not more involved in the fine points of
platinum/palladium. Yes, I have read about the POP approach with ziatype
but the humidifying aspect is daunting. We already use EDTA to clear prints
followed by sodium sulfite if the EDTA wasn't sufficient.
I don't teach mordancage.
For the past few years the main thing I have been learning about is the
production of digital negatives to print in non-silver processes. It looks
as if
you are into this also. I have both editions of Dan Burkholder's book and
The University of the Arts now has a Scitex imagesetter. More and more the
students are using various kinds of digital negatives. For my own work I am
scanning my 8 x 10 pinhole negatives and developing an alphabet of figures
and
objects with which to create meanings beyond what I can orchestrate in real
life.
Sarah Van Keuren
>
>
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