[pure-silver] Re: KRST (was Sistan and Senior Moments)
- From: "Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
- To: <pure-silver@xxxxxxxxxxxxx>
- Date: Fri, 17 Aug 2007 11:17:02 -0700
----- Original Message -----
From: "Adrienne Moumin" <photowonder2010@xxxxxxxxxxx>
To: <pure-silver@xxxxxxxxxxxxx>
Sent: Friday, August 17, 2007 9:49 AM
Subject: [pure-silver] KRST (was Sistan and Senior Moments)
Humpf. Not sure who to believe at this point, Kodak or
the speculators!!
So I guess I'll keep on using it 1:19; although I will
test some reject prints w/the stronger dil. to see if
there's a discernible color change. Better safe than
sorry.
Not speculation at all but the results of extensive
research by the Image Permamence Institute of the Rochester
Institute of Technology.
I can't find the citation to the original research on KRST
but its mentioned in a paper describing sulfite wash aids
(1).
This paper mentions the use of diluted KRST and points
out that even with its use the vulnerability of microfilm to
oxidative attack is greater when it is overwashed. The
effect of overwashing was investigated by the IPI in the
research leading to the report mentioned below, it was not a
factor in the failure of KRST to protect the NEH microfilm
or other microfilm found to have the same problems.
The RIT research was done for the National Endowment
for the Humanities in 1991, the full title is:
_Final Report to the Office of Preservation National
Endowment for the Humnities
Grant No. PS-20152-57_
_Sulfiding Protection For Silver Images_ James M. Reilly,
Kaspars M. Cupriks, Image Permanence Institute Rochester
Institute of Technology, March 38, 1991
Reprints are available from the IPI.
While this paper addresses microfilm and not printing
paper there is enough similarity in the emulsions to think
its valid for paper also. I also had several private
conversations with Dr. Douglas Nishimura, a scientist at IPI
with direct involvement in the research who stated to me
that KRST at 1:19 was NOT completely effective for paper for
the reasons stated for microfilm in the above document.
A more effective treatment is a Liver of Sulfur type
sepia toner. IPI concocted their own version intended to
have low odor but packaged toners are quite effective. These
include Kodak Brown Toner and Agfa Viridon of the second
type. Kodak published formula T-8 is also effective.
Kodak has published a paper on the use of KBT for
microfilm protection. It is Publication No. A-1671, _Use of
Kodak Brown Toner to Extend the Life of Microfilm_
available on-line from the Kodak site.
1, _The Effect of Salt Baths on Hypo and Silver
Elimination_ R. W. Henn, Nancy H. King, J. I. Crabtree,
Kodak Research Laboratories, 1956 "Photographic Engineering,
Vol7, NOs 3&4, p.153ff
This paper also has a considerable bibliography of
research papers pertaining to fixing and washing.
---
Richard Knoppow
Los Angeles, CA, USA
dickburk@xxxxxxxxxxxxx
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