From: Judy Seigel (jseigel@panix.com)
Date: 10/14/02-10:23:49 PM Z
On Mon, 14 Oct 2002, David Eastman wrote:
> No experience with Cyanotype myself...
> But I noticed a discrepancy in two posts here and
> would like to see whats what.
>
> Laim wrote:
>
> "...your paper just might be unsuitable. Once I
> coated some scraps of paper for tests, using an
> Arista APH film box for support. Instant deep blue
> colour where I got some sensitiser on the box.
> > Probably the box was acidic. Just did a test - added
> a dash of tartaric acid solution to freshly mixed
> cyanotype goo - it turned blue.
>
> Then Judy wrote: "Cyano doesn't like alkali. Acid is
> OK."
>
> Did Judy make a Boo Boo?
David, I think you misunderstand the discussion (tho why you didn't ask
"did Liam make a boo boo?" is perhaps as interesting as other questions at
hand).
I assumed Liam meant he added tartaric acid solution to cyano emulsion...
a combo i've never heard of, or maybe it was to cyano toner for silver
gelatin. I don't know how much cyanotype printing Liam has done, tho he's
world class master of cyano toning of silver gelatin... which, tho the
colour is the same, is quite a different process. Anyway it isn't clear to
me that adding tartaric acid to freshly mixed cyano goo was, um, defining.
Meanwhile, what cyano "likes", by which I mean *cyanotype*, is acid in the
wash water, for instance. John Dugdale gets his best blue with a bit of
pineapple juice in the first rinse (supposedly containing citric acid...
he's the organic type.)
> Laim adds: "Doubt if anyone makes acid art papers, but
> could be a drop of acid has got into the system
> somewhere."
The danger is buffered papers, buffered mat boards, buffered portfolio
boxes, etc. I don't know of anyone deliberately making acid art papers,
but it happens...
> I don't know about that... I tested some papers about
> 5-6 years ago... a lot and found quite a few to be
> acidic! Not all of these were drawing or watercolor
> papers, but they were all potential substrates for
> sensitizing. Also, not all Japanese papers I tested
> were ok either.
Yes, as I think I mentioned on the list (I know I wrote about it in
Post-Factory section on paper for cyanotype), one year an Arches paper
proved to be acidic, as gave great trouble to hand-made paper book makers
buying the stuff at NY Central, but Arches only repeated "it's not
acidic." The reason Light Impressions sells a pH pen, is exactly to test
your papers.
But if a paper were acid, it would anyway tend to neutralize during the
wash -- except some folks dump a bottle of vinegar in first wash... Etc.
> Judy continues...
> "One other thought comes to mind-- I have a
> recollection of cyano turning blue on a cheap pulpy
> paper, which we figured had some kind of alum in it."
>
> This could have been the case... Not sure about all
> the "alums", but isn't Chrome Alum is acidic?
I don't have a clue if chrome alum
is acidic or not -- but acid ALONE is obviously not the defining quality
of any chemical, paper, or emulsion. Alum for instance has other
properties, one of which we suspected was interfering with cyanotype
printing. That of course was only a guess at the time, and now a 15-year
old memory dredged up to explain a problem that has since been restated.
Now we see the presenting symptom was precipitation on combining A&B, not
on the paper. So the paper is not the issue in any event, nor is the wash
water, nor the mat board, nor anything except the chemicals themselves.
Judy
This archive was generated by hypermail 2.1.5 : 11/14/02-02:40:26 PM Z CST