Re: Does anyone know this person or the work (late)

From: Jean-Paul Gandolfo <jpgalt@infonie.fr>
Subject: Re: Does anyone know this person or the work (late)
Date: Thu, 16 Sep 2004 13:29:41 +0800

> Sorry to reply so late to your question sent last august. but I was out
> of my home for a long time. I teach BW silver based and alternative
> processes at Louis Lumiere school and, with my friend Bertrand Lavedrine,
> we were the supervisors of the study you quote in your message.

Thank you so much for your description of Emmanuel Bénard's
work. Enhancing permanence of b&w prints with polysulfide treatment is
one of my interests for exactly the same reason as you mentioned.
Since the material varies considerably and polysulfide treatment is
very versatile for visual effects as well, I think what is most
important is a quick test that can be used to asses adequacy of
protection for a particular material and a particular technique
developed by each darkroom worker. (Johnsen et al from the National
Museum of Denmark studied this with film material in selenium toner,
and saw 70% conversion in Plus-X while 10% conversion in T-MAX 100 in
the same treatment, according to a brief summary in ICOM Committee for
Conservation preprints 1993, and this is enough to convince me that
testing in each darkroom is highly preferred if permanence is of
importance.). Standard ISO dichromate bleach technique causes
difficulty with stain and this necessitates filtering during
densitometry. Peroxide immersion technique makes relatively small
density change to be a reliable test in ordinary darkroom. Peroxide
fuming test takes too much time. Ferricyanide bleach seems to work
very well in my personal experience but good published data are
lacking.

Did you compare the Farmer's reducer (ferricyanide) test against
standard dichromate, peroxide fuming or X-ray fluorescence and come up
with a recommendation for criteria? In your findings, is 60% remaining
density with Farmer's a useful criterion just like in the case of
dichromate?

> Emmanuel Benard is now far away from conservation field, I think he is
> working for a local radio broadcast network in the south of France.
> Scholarship is one thing, life another one ...

Indeed... you just need to find students whose life is one form of
photography and scholarship is another form of photography... problem
solved :-)

> I am always interested in collecting informations from people involved
> in baryta oxydation problems.

I also found out that Christopher Gmuender's thesis at RIT is on a
related topic. The title of the work is "On black-and-white paper
image-stability enhancement: effectiveness of toning treatments on
silver gelatin determined by the hydrogen peroxide fuming test" (MFA
Thesis Report, Rochester Institute of Technology, 1992). I found this
reference in the context of Silver Lock and photographic prints with
peroxide fuming test, in "A summary of recent research at the Image
Permanence Institute (1992)" but could not find the thesis itself at
RIT website.

Another interesting study I found is by a Konica group of Chika
Honda. They were concerned about permanence of medical radiographic
films, and they found peroxide fuming test to be too powerful for
predicting image degradation in relatively short useful life of
medical records (a few years) stored in office environment. So they
used compressed oxygen at elevated temperature and humidity, and
compared the accelerated results against real-life samples. They also
found that some antifogging agent (1-phenyl-5-mercaptotetrazole) used
in the developer solution effective in stabilizing the image. He was
kind enough to share more of his results and insights with me than
those published, but unfortunately he has moved on to new projects.

Thank you for your information and please let me know if there is
anything else I can read to learn more about the work from your team.

--
Ryuji Suzuki
"You have to realize that junk is not the problem in and of itself.
Junk is the symptom, not the problem."
(Bob Dylan 1971; source: No Direction Home by Robert Shelton)