[pure-silver] [pure-silver]Old & new KRST. Was Selenium followed by T-8 Polysulfide
- From: "Tim Rudman" <ps@xxxxxxxxxxxxxxx>
- To: <pure-silver@xxxxxxxxxxxxx>
- Date: Sat, 18 Dec 2004 20:08:07 -0000
I have just been catching up on all the PS mail, having finally surfaced
from a ton of paper mail after 3 months away!
I remember having quite long e-discussions with Dr Nishimura when I was
finishing the archival toning section of my toning book. We discussed,
amongst many things, this question of a possible change of formulation for
KRST. I think we should be a little cautious about this becoming legend and
passed on as fact. Whilst it could be true, according to Doug Nishimura IPI
were not able to demonstrate this as an explanation to account for their
observations (there could be other explanations). Kodak had no record of any
such changes and indeed when IPI got hold of an old (1970s) bottle of KRST
they tried using it in a repeat experiment to see if they could measure any
significant difference in behaviour between "new" and "old" toner and they
behaved the same way. He went on to say 'that since we haven't found any
solid evidence that there was indeed active sulfur in the old bottles of
selenium toner our suggestion that sulfur might be involved is purely
speculation.' This does not of course rule it out, - nor in.
I doubt that this contributes much to the discussion here in practical terms
though!
Tim
-----Original Message-----
From: pure-silver-bounce@xxxxxxxxxxxxx
[mailto:pure-silver-bounce@xxxxxxxxxxxxx] On Behalf Of Ryuji Suzuki
Sent: 16 December 2004 19:08
To: pure-silver@xxxxxxxxxxxxx
Subject: [pure-silver] Re: Selenium followed by T-8 Polysulfide
From: Lloyd Erlick <lloyd@xxxxxxxxxxxx>
Subject: [pure-silver] Re: Selenium followed by T-8 Polysulfide
Date: Thu, 16 Dec 2004 09:45:18 -0500
> My last attempt, which I considered successful, was a small amount of
> sulfide dissolved in my working solution of selenium toner. I did find
> a small enough amount that the odor stopped bothering me, and that
> amount did not have a large effect on the final print tone compared to the
selenium.
Did you add sulfide or polysulfide? They are different.
Adding polysulfide used to work for me but when I used up my old bottle of
KRST and switched to a new bottle of KRST several years ago, this method
never worked. Once the polysulfide is mixed to KRST, it degrades in a matter
of several minutes and the solution stains prints. I tried to mix KRST and
KBT, and also mixed in liver of sulfur obtained from a different source, but
all made the similar results. So I abandoned this route and now I make
selenium-polysulfide toner similar to POLY toner from scratch.
Change in KRST was noted by people outside the IPI as well. They were not as
active in sharing their findings as IPI. Conservation scientists at National
Museum of Denmark found that the processing capacity of KRST bath was
decreased some time during 1990's. They routinely do quality control tests
for every so many prints made in their darkroon.
--
Ryuji Suzuki
"Keep a good head and always carry a light camera."
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