From: Robert W. Schramm (schrammrus@hotmail.com)
Date: 04/15/00-02:33:36 PM Z
I did some actual tests on the effects of heat drying (via hairdryer)
on cyanotype and Vandyke Brown and found that there was a definite
loss of contrast (1 to 2 steps on a 21 step wedge) when heat was used
as compared to air drying (small fan).
Although I have not checked this with platinum, it might be worth
looking into. Also there is the problem of the hairdryer causing little
particles of platinum sensitizer to flake off and float around
in the air you are breathing which, I assume, is not a good idea.
I have also noticed that platinum is very sensitive to humidity. I
have found that problems seem to emerge when the humidity is very
low. Also I have found grain to be a problem when the humidity is to
high if you use potasssium chlorate as a contrast control agent.
Bob Schramm
>From: Eric Neilsen <e.neilsen@worldnet.att.net>
>Reply-To: alt-photo-process-l@sask.usask.ca
>To: alt-photo-process-l@sask.usask.ca
>Subject: Re: Ferric Oxalate and microwaves
>Date: Fri, 14 Apr 2000 17:18:26 -0700
>
>Stephen, It has been my experience that microwave use is ok if it is short
>burst
>and not used to generate too much heat. that will be different for every
>user due
>to all the factors involved; amount made, wattage of microwave.....
>
>If you try it and it works, great. I haven't had the need to use it for
>myself as
>I make a liquid ferric. I did however use a microwave recently to help get
>some
>Artcraft ferric into solution. I have found, along with the testing that
>Jeffrey
>was doing, that all powder ferric is not the same and some oxalic acid is
>required
>to get it into solution at certain levels. Glad to hear that your sky
>specs are
>gone.
>
>And a thought that I had about those pesky specs..... Many use hairdryers
>to dry
>there prints. Some of these might have small amounts of rust that get blown
>out on
>to the paper. We love clean air too, air purification requires moving air
>as does
>AC units to make some rooms comfortable. I wonder if some of these indoor
>air
>currents are the source of small particle of rust from fans, blowers,
>grates,
>ducts, etc.???
>
>EJ Neilsen
>
>Stephen Harrison wrote:
>
> > >Nick Makris wrote:
> > >> ... I found the best
> > >> way was to buy FO powder that readily dissolves in boiling distilled
>water.
> > >> ...
> > >I must confess that I do microwave my ferric oxalate for 18 seconds.
>The
> > key for me is filtering the result with a #2 Whatman filter in a flask
> > filter. For the first time in my life, I have very few problems with my
> > ferric oxalate. It seems to work well. Skies are clean and without
>pits.
> >
> > Stephen Harrison
>
>--
>Eric J. Neilsen
>4101 Commerce Street, Suite #9
>Dallas, TX 75226
>214-827-8301
>http://e.neilsen.home.att.net
>http://www.ericneilsenphotography.com
>
>
Check out my web page at:
http://www.geocities.com/schrammr1/schramm_studioa.htm
also look at:
http://www.wlsc.wvnet.edu/www/pubrel/photo.html
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