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

Dear Ryuji

Ryuji Suzuki a *crit :

>
> 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?

The scope of the study wasn't to compare dichromate and farmer used as
reducers. We were aware of the problematics associated with dichromate and we
make the choice of Farmer as an alternative answer. The conversion ratio in
high densities ranged from 18 to 29% with our method. Indeed, theses mesures
as lower, compared with the results you can get with dichromate but the stain
is out, the ISO recommendation too...

>
> 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.

At the time of the study we get some information, with the help of Jim Reilly
(IPI) about the document you quote. The author admits the effectiveness of
peroxyde fuming method. He makes interesting remarks about toner bath
ageiing,, a shadow part of toning practices. A lot of work has to be do to
lighten the field. The polysulfide treatments were applied with low dilution
(10, 25, 50). I don't see the paper tests but I guess the hue was probably
very warm.

> 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

If you have the quote, I am interested in getting it.

I will be at Cologne Photokina opening end of the month in germany. I will try
again to speak with paper makers about oxydation, specialy Agfa team. We made
some tests with Sistan, some yeras ago, it's a thyocyanate based product
giving a more stable silver complex and the treatment is really usefull to
prevent oxydation risk. Agfa people are very nervous about the topic and this
year, probably the bad weather blowing on BW silver market will be not able to
help me ...

Best regards

Jean-Paul GANDOLFO
Louis Lumiere National School of Photography
Marne-la-Vallée
France
www.ens-louis-lumiere.fr
Received on Fri Sep 17 04:25:17 2004