From: Judy Seigel (jseigel@panix.com)
Date: 07/30/02-11:51:32 AM Z
Eric, for best results with cyanotype, lose the oxalic acid AND the
dichromate AND the heat dry.
That done, almost any paper that's not too slick to absorb emulsion is
fine. (Except BFK, which only performs if your name is Bob Schramm.)
Proof, at least from my own extensive testing, is documented in P-F #5.
The one with the oxalic acid I call "OX-2: the other cyanotype formula" I
found it inferior to the plain 2-ingredient formula in readiness, keeping,
and clearing, except for a couple of days after mixing, when it may be
brighter.
But I would NOT NOT NOT under any circumstances heat-dry cyano. Or let me
say that in all of a dozen or more tests I & my students have done, it
blew out the values, sometimes a lot, sometimes less, but always degraded.
Moral: Cyano is not pt/pd, which improves with, in fact (AFAIK) requires
heat dry and many ingredients.
Judy
On Tue, 30 Jul 2002, Eric Nelson wrote:
> I'm doing a cyanotype project this week and it's been
> years since I've monkeyed w/this process.
>
> My question is, using the formula below, (unless I
> hear otherwise), what is the best/favorite paper using
> brush application? At this moment I'm testing Platine
> since I have that in the lab, but the first test was
> kinda poopy, (i.e. weak shadows, blotchy).
>
> I am changing the length of time the sensitizer sets
> before using the hair dryer to see if that helps.
> Also, it's a hot steamy day here in Chicago but have
> AC in the lab and I'm using sunlight to expose these.
>
> Thanks for any and all help!
>
> Eric Nelson
>
> Solution A:
> Ferric Ammonium Citrate 27.2 gm
> Oxalic Acid .5
> Water to make 100 ml
>
> Solution B:
> Potassium Ferricyanide 9.2 gm
> Oxalic Acid .5 gm
> Ammonium Dichromate 0.2 gm
> Water to make 100 ml
>
>
>
>
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