[pure-silver] Re: Direct toners- the Viradon mystery
- From: Richard Knoppow <dickburk@xxxxxxxxxxxxx>
- To: pure-silver@xxxxxxxxxxxxx
- Date: Sun, 26 Jun 2005 05:15:06 -0700 (GMT-07:00)
-----Original Message-----
From: Christopher Woodhouse <chris.woodhouse@xxxxxxxxxxxx>
Sent: Jun 26, 2005 1:56 AM
To: "pure-silver@xxxxxxxxxxxxx" <pure-silver@xxxxxxxxxxxxx>
Subject: [pure-silver] Direct toners- the Viradon mystery
Until recently I have always used odorless sepia toners, normally
indirectly, following a short bleach. Having seen some prints of Ralph's I
thought I would try Viradon 'new' for the first time and was amazed at how
it reacted in the wash. I know all that stuff about using a Bisulphate stop
bath, but what I was wondering is it goes against everything I thought I
knew about chemistry. I always thought that chemical activity goes down with
lowered concentration. Watching through the side of my archival washer, the
print continues to get browner and browner, changing even after 20 minutes
gentle washing.
I'm intrigued, what is the mechanism that allows it to continually change
colour when the concentration must be extremely dilute? I thought for a
laugh I would put another print into extremely dilute Viradon - nothing
seems to happen. What am I missing? (polite responses only!)
--
Regards Chris Woodhouse
This is a well known characteristic of Polysulfide toners. They have the
strange property of toning faster as they are exhausted or diluted. I don't
know the chemical mechanism. A pretty strong sodium sulfite bath (10%) acts as
a stop bath but the print should be washed quickly especially at first. If the
toner is dilute enough it can result in a peach colored stain. Kodak Brown
Toner behaves the same way. Kodak Hypo Clearing Agent stock will work instead
of the sulfite bath (since its buffered sulfite at about 10%) but is an
expensive substitute.
How extremely dilute was the experiment?
--
Richard Knoppow
dickburk@xxxxxxxxxxxxx
Los Angeles, CA, USA
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