Re: Taming Fabriano Artistico (Trad. White) for Cyanotype

[Paul Viapiano <viapiano@pacbell.net>]

The reason I use oxalic acid and not HCl is because of its relatively benign 
handling characteristics. By comparison, HCl is just too dangerous a 
chemical to have in a darkroom located in your everyday household.

The whole idea of paper acidification is to lower the pH of the paper and/or 
remove the excessive amounts of carbonate coating manufacturers use in order 
to achieve the almighty 'acid-free' status, in order to be amenable to the 
acidic solutions we use. So, I don't think there is an advantage to using a 
much stronger acid. After all, acidic soaking aolutions of only 1-8% are 
used by printers worldwide with wonderful results. Not only oxalic acid can 
be used, but citric works very well, and I even used a very dilute solution 
of Kodak Indicator Stop Bath once. It worked wonderfully...and I would 
expect plain distilled white vinegar to work as well.

Try amending your coating with a drop per ml of Tween or Photoflo at 10% to 
help prevent runoff in the first wash...works wonders for me.

Paul



----- Original Message ----- 
From: "Christina Z. Anderson" <zphoto@montana.net>
To: <alt-photo-process-l@usask.ca>
Sent: Wednesday, December 03, 2008 7:10 AM
Subject: Re: Taming Fabriano Artistico (Trad. White) for Cyanotype


> Ammonium ferric citrate (why is it written this way--can it equally be 
> written ferric ammonium citrate or is that a chemistry no no?) has bigger 
> molecules than  ammonium ferric oxalate and hence is harder to absorb in 
> the paper so I have been told (not being able to see it with my eyes :)) 
> but I have not personally had a problem with bleeding although I certainly 
> do see blue water from washoff.
>
> What do you mean by "peptization" Loris?
>
> And is there a conservation difference in paper that has been treated with 
> HCL vs. oxalic acid, I wonder?  Or have I watched too many horror movies 
> where someone's face melts when acid is thrown on it?
>
> One last thing, in a convo with Sam I stand corrected--cyano does not 
> change to a lighter blue with dilution he did say, but he actually also 
> said with major dilution it does--1:6 or so.  So it seems Henry, Sam and I 
> are all on the same page with that one. I don't do any cyanotype just for 
> cyanotype's sake as he does (and as I've said there is a gorgeous 
> cyanotype of Sam's in the two page centerfold of the Peek book to prove 
> it).
>
> I find it fascinating that cyanotype is so versatile.
> Chris
>
>
> As a final note, I must add that I got the least amnt. of peptization
> bleeding (w/ Traditional Cyanotype) I've seen so far, with neutralized
> /acidified Fabriano Artistico... Development water was pretty blue-free
> (which to me is not the case with other papers). Maybe the acid is doing
> something to the size and/or fibers so that they can retain the colloidal
> Prussian Blue particles better, or something like that. Who knows?
>
> Regards,
> Loris.
>
> P.S. The print was made on the (softer / more textured looking) back side
> of the paper (watermark reads backwards).