From: Neil Miller (neil@miller.gioserve.com)
Date: 01/22/03-02:57:14 AM Z
Hello Judy,
Yes, I am in the UK. Just a bit of background to my stock of brown(green!)
and green(green!) FAC....
I started making cyanotypes - with some success - after subscribing to your
wonderful journal. After a lot of reading about this and other processes I
began to wonder why my FAC was a brownish/burnt-orange colour, although it
said green on the label. I arranged with the supplier to send a sample back
for testing. Supplier sent it to manufacturer, manufacturer tested it, gave
it the thumbs up, said it was green in type if not in colour and furthermore
they often made FAC of a range of colours between distinctly brown through
to green depending on where they purchased the raw supplies from. It was
all "green," though. Sounds a bit suspect, doesn't it?!
Anyway, just for reassurance I ordered a new lot from another supplier and
it turned out to be a faint lime green colour, which I thought was more in
keeping with the description on the bottle and which I now use exclusively.
I still have some of the older stuff left and I will try that out and let
you know.
I wish I knew how to test the tartaric acid, but I'm not too well-up on
things chemical - if you know a simple test I would be grateful.
Thanks,
Neil.
----- Original Message -----
> Neil, where are you? Possibly in the UK? Because Spirits of Salt comes
> from there of course -- and that's the first I've heard about precipitate,
> milky, whatever, with VDB -- I probably have entries for the process in 15
> books, and have led, pushed, or followed 100s of space cadet undergrads
> through it, and never seen what you describe -- except the one time we got
> fake distilled water at the local hardware store, and that simply
> precipitated out the silver, as silver chloride, bam, right to the bottom
> of the cup, dead. And as I said, I've found that if I get impatient and
> pour too fast,it still goes right back into solution.
>
> What comes to mind now, though, reading your description, is Mike Ware's
> term for ferric ammonium citrate, something about it being (if I remember
> the phrase correctly) "ill defined," or maybe it was "ill characterized,"
> meaning it's not one precise identical substance but has a lot of wiggle
> room and still "F A C." (Somewhere I have that in the file, but probably
> someone else knows the exact term.) I have seen brown FAC (it performs
> differently BTW, is slower for one thing), but never "brown" that was
> supposedly "green." Etc.
>
> In any event, sounds to me like your FAC is EXCEPTIONALLY ill defined.
> For curiosity, if nothing else, you might want to get a small quantity
> from another supplier to compare.
>
> The other thing is, have you tested your tartaric acid? Maybe it's
> something else... Or dead. ?
>
>
> Judy
>
--- Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.427 / Virus Database: 240 - Release Date: 06/12/2002
This archive was generated by hypermail 2.1.5 : 02/21/03-10:44:17 AM Z CST