[pure-silver] Re: Thiourea and Thiourea dioxide
- From: <C.Breukel@xxxxxxx>
- To: <pure-silver@xxxxxxxxxxxxx>
- Date: Thu, 24 Feb 2011 14:30:34 +0100
Hi Eric,
I am surprised here: FSA is my favorite toner. I use it mostly on partially
toned prints, because the density gain is considerable (your image can get 1-1
½ stops darker on a completely bleached print, depending on the paper). I like
the flexibility of the different bleaches.
Redevelopment (FSA is not really a toner, see Tim's book) in FSA is generally
very fast: 30 sec-1 min., exception is after the Iodine bleach, than
re-development takes a lot of time (by heart: 30 minutes or so)
Good luck,
Cor
Btw my FSA http://tinyurl.com/669jflo
Good luck,
Cor
________________________________
From: pure-silver-bounce@xxxxxxxxxxxxx
[mailto:pure-silver-bounce@xxxxxxxxxxxxx] On Behalf Of Eric Nelson
Sent: woensdag 23 februari 2011 21:45
To: pure-silver@xxxxxxxxxxxxx
Subject: [pure-silver] Re: Thiourea and Thiourea dioxide
It worked ok-ish in that I did get toning eventually; it's very slow, and if
you bleach too far tone doesn't come back as it does when sepia toning.
It is a totally different process, and I understand that. The color I got was
nice yellow-greenish brown.
What I'd really like to find is a toner (besides tea and coffee) that adds a
cream color to the paper. Presently just working with RC postcard paper so
extended toning and washes aren't a best choice although w/RC I assume longer
washes aren't necessary anyway. I'd just hate to send out a promo and have it
turn brown.. i.e. brown in a bad way!
Eric
________________________________
From: Ray Rogers <earthsoda@xxxxxxxxx>
To: pure-silver@xxxxxxxxxxxxx
Sent: Wed, February 23, 2011 11:50:52 AM
Subject: [pure-silver] Re: Thiourea and Thiourea dioxide
Correct... not all sites show a difference.
I think the FSA or thiourea dioxide toner is more for a special effect. Since
you read about it in Tim's book, did you get the result you were after, even
though it was slow in working?
I suspect you didn't, in which case you might need to spring for it, if that is
really a look you are after....
Ray
--- On Wed, 2/23/11, Eric Nelson <emanmb@xxxxxxxxx> wrote:
From: Eric Nelson <emanmb@xxxxxxxxx>
Subject: [pure-silver] Re: Thiourea and Thiourea dioxide
To: pure-silver@xxxxxxxxxxxxx
Date: Wednesday, February 23, 2011, 3:57 PM
I looked it up myself and found these for t. dioxide with the 2
different CAS #'s:
http://www.lookchem.com/cas-418/4189-44-0.html
http://www.thiourea-dioxide-fas.com/ <--CAS# 1758-73-2
This is what I found for my thiourea:
http://www.jtbaker.com/msds/englishhtml/t3107.htm
I won't pretend I know anything about what's on those pages as I'm just
looking for the practical application of the compound with this toner.
I used my thiourea anyway as I was in a testing mode yesterday and did
get toning, albeit very slowly, of the prints I had bleached with the
ferricyanide/pot. bromide combo. That may be my "practical" answer right
there, but since I work w/chemicals w/o getting into molecular structures and
formulas, I'm hoping someone who does might know the answer if it's 'worth'
looking into getting the t. dioxide or not.
Eric
________________________________
From: Ray Rogers <earthsoda@xxxxxxxxx>
To: pure-silver@xxxxxxxxxxxxx
Sent: Wed, February 23, 2011 4:45:55 AM
Subject: [pure-silver] Re: Thiourea and Thiourea dioxide
Sources I looked at gave different yet presumably equvilant structures for
those two cas #s
Thiourea is different.
???
Thiourea sulfoxide?
Did you mean thiourea dioxide rather than sulfoxide?
(Can you supply the CAS # for that?)
Ray
--- On Wed, 2/23/11, daniel <daniel.bouzard@xxxxxxxxxx> wrote:
From: daniel <daniel.bouzard@xxxxxxxxxx>
Subject: [pure-silver] Re: Thiourea and Thiourea dioxide
To: pure-silver@xxxxxxxxxxxxx
Date: Wednesday, February 23, 2011, 7:01 AM
Hello,
CAS 4189-44-0 and 1758-73-2 are both for thiourea dioxide under
different names. CAS 62-56-6 is for thiourea.
Several years ago I tried toning with thiourea sulfoxide following Tim
book and it worked very well.
Daniel Bouzard
Le 22/02/11 23:25, Eric Nelson a écrit :
I'm working from Tim Rudman's toning book and am playing with the FSA
toner.
In it he lists thiourea dioxide to be used in the toning bath. Now I
have thiourea that comes from TechChem down in Missouri and called them to see
what flavor of thiourea I have. Bob called back and he found something odd in
the CAS listings.
TechChem's thiourea is CAS# 62-56-6
Thiourea dioxide has TWO CAS #'s which he says is "unheard of".
CAS# 4189-44-0 and CAS# 1758-73-2
Since Tim has been known to hang around these parts and others here may
be more familiar with the CAS catalog system, I'm wondering if these 3
compounds are interchangeable or what?
Thanks
Eric
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