[pure-silver] Re: Direct toners- the Viradon mystery

During storage solid sulfur is formed due to decomposition of the polysulphide ion. In other words the active ingredient itself is lost.

Walter

janet ness wrote:
A related question: is it possible to reuse Viradon toner? I notice that used Viradon acquires solid, waxy chunks of something after storage. I've been filtering and reusing it, but threw it out when it started to look like orange juice. Is anything lost in filtering?
Janet Ness

    ----- Original Message -----
    *From:* Richard Knoppow <mailto:dickburk@xxxxxxxxxxxxx>
    *To:* pure-silver@xxxxxxxxxxxxx <mailto:pure-silver@xxxxxxxxxxxxx>
    *Sent:* Sunday, June 26, 2005 5:15 AM
    *Subject:* [pure-silver] Re: Direct toners- the Viradon mystery



    -----Original Message-----
    From: Christopher Woodhouse <chris.woodhouse@xxxxxxxxxxxx
    <mailto:chris.woodhouse@xxxxxxxxxxxx>>
    Sent: Jun 26, 2005 1:56 AM
    To: "pure-silver@xxxxxxxxxxxxx <mailto:pure-silver@xxxxxxxxxxxxx>"
    <pure-silver@xxxxxxxxxxxxx <mailto: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 <mailto:dickburk@xxxxxxxxxxxxx>
    Los Angeles, CA, USA
    
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