Re: sulfiding treatment and testing methods (was Re: Does anyone know thisperson or the work)

From: Jean-Paul Gandolfo ^lt;jpgalt@infonie.fr>
Date: 09/19/04-08:34:31 PM Z
Message-id: <414E41B6.5D704604@infonie.fr>

Ryuji Suzuki a *crit :

>
> That is understood, and one issue with ferricyanide bleach is that its
> oxidative power fluctuates unless its action is "buffered" with
> ferrocyanide. (Its oxidative power is very strong at the beginning of
> bleaching and it gradually weakens.) So I wish there were a standard
> stabilized ferrocyanide bleach for this testing purpose with its
> testing results compared to peroxide fuming tests... It's easy for me
> to do the bleach part but I'm not set up to do the fuming tests...

You are right,. The ferricyanide oxydation parameter is important (ageing,
shaking ...). We have used a one shot approach during the study.

> By the way, how many seconds do you treat your prints in your dilute
> SilverLock solution at what temperature?

Kodak Polymax
Dilution 1: 1600, T 20C, one minute

Ilford Warmtone
Dilution 1 : 4000, T 20C, one minute

Ilford Galerie
Dilution 1 : 4000, T 20C, one minute

Agfa MCC 111
Dilution 1 : 3200, T 20C, one minute

The aim was to avoid a perceptible yellowing of low density areas on the
samples.

> > 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.
>
> I've used comparable concentrations with a few of my favorite papers
> developed in phenidone-ascorbate neutral tone developer of pH 10.3.
> (Note however that my toning solution contains both polysulfide and
> selenium like Kodak POLY toner and AGFA Viradon before they
> changed... these are not used for microfilm but I like them for
> prints.) Papers like Agfa MCC and MCP gives very slight hue shift in
> 30 seconds in 1:20 strength, but bleaching test indicates that the
> treatment is effective. Longer toning with these papers will give
> black brown or purplish brown hue, which is of course more resistant
> to oxidation. On the other hand, Forte Fortezo paper gives visible
> warming even in a 15 second treatment, and the hue continues to shift
> to orange brown. All these toning is at room temperature (25C).

I made some tests, in the last year mixing Viradon and Kodak selenium
toner. Good toning results but the smell was beyond strong ...
The mixing of KST with Kodak brown toner has a better smell but the
results aren't similar.

>
> > > 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.
>
> > If you have the quote, I am interested in getting it.
>
> The abstract is:
> http://www.imaging.org/store/epub.cfm?abstrid=1971
> There was a full paper published in the journal, which I can send you
> when I'm back in office.

Thank's for the paper.

> The abstract very briefly mentions the positive effect of PMT, but the
> full paper omits that part altogether. So I contacted Chika Honda and
> asked for a bit more details. He did not publish the results for that
> part in any language, but maintained that his results were positive
> about PMT's image protecting effect when added to the developer bath.
>
> I have personal experience with Sistan, but all I have is anecdotal
> reports when it comes to its efficacy. Another compound of interest is
> 2-(amidinothio)ethanosulfonic acid, which is the active ingredient of
> Fuji Ag Guard. I bet these treatments with soluble compounds will be
> harder to assess for their efficacy correctly using bleach tests, and
> fuming tests are called for.

Two years ago, we have tried to induce oxydation spots in room conditions
(with paint or varnish solvants, heat, light ...). No results were get in
spite of a three months lasting test. Last year we had a strong heatwave -
with high level of ozone pollution- in Paris area during summer. I let a
BW print on my desk at the bottom of a book stack. In september I can see
a nice bright yellow toned print. This one was in contact with a fresh
printed offsed computer catalog. Temporary conclusion : heat/pollution+
peroxydes/contact/darkness ...
In an other way, we think that overwashing of baryta papers, specialy with
hard water and vertical washer, can induce the oxydation problem. In many
cases, very consciensous printers were involved in oxydation conflicts.

>
> > Agfa people are very nervous about the topic
>
> I've heard of rumors that they aren't very enthusiastic about testing
> efficacy of Sistan but I wonder why.

Something like you eat drugs every day but you aren't ill. Easy - too
easy - shortcut ...
More seriously, the tests we made show an improvement of photographic
stability with Sistan, specialy with Agfa papers. I think Agfa has run
these tests (private talks in Photokina 2000 help me to have this feeling)
but they don't want to communicate about that.

>
> Best regards from Paris

Jean-Paul GANDOLFO
ENS Louis Lumiere
BP 22
93161 Noisy-le-Grand CEDEX
FRANCE
Received on Mon Sep 20 08:40:33 2004

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