Re: Eastern European RC papers

Date sent: Mon, 23 Jan 2006 14:23:19 -0500 (EST)
From: Ryuji Suzuki <rs@silvergrain.org>
Subject: Re: Eastern European RC papers

> Although your suggestions are good ones, I think the real problem is
> somewhat blurred. Lack of gelatin overcoat and insufficient gelatin
> hardening may be seen as a problem by some users (such as students who
> don't handle RC prints carefully) but I don't think they are closely
> related to archival property given proper handling.
>
As I know the hardened gelatine a bit more sealing the
silver contents against the humidity and air pollution.
 
> For example, I've been making enlarging and contact printing emulsion
> with no protective layer for some years but with careful handling I
> have not seen a problem.

The mentioned sealing is (much) better with a
protective layer (up to quality) which is an UV filter also
in some case. The best example is in my earlier
message:
http://duke.usask.ca/~holtsg/photo/current/0306.htm
I will try to found my photos about it and show it on my
site (but I need some time for this).
I think with optimal storage/process conditions the
first silver problem appearing after a long time: 50
years or more. (In the case of developing out
materials.) The dry plates in my example about 100
years old with average or worse storage conditions in
that period...
>
> This kind of image deterioration involves redox reactions. RC paper
> has a generator for a strong oxidizing agent in the polyethylene
> layer, for which companies in the west spent considerable effort (and
> many mistakes) in 1970s, 80s and early 90s. Manufacturers like Ilford
> and Kodak told users that the image deterioration was caused by poor
> processing and washing, and the problem does not lie in their
> products, while they secretly improved the formulation of the resin
> coat. And every time Kodak said there was no more problem with their
> RC papers, a new problem was found.

In normal case to eliminate the bad effects of the base
material is the task of the substrate and/or baryta layer
(a seal problem again). Do You think that layer cannot
handle this problem in a few products?
>
> But putting too much focus on the RC is also very misleading in my
> view, because simply using baryta paper does not ensure good
> permanence. The most effective way to prevent such deterioration,
> regardless of RC or FB, is to (1) treat the print in a sulfide toner,
> AND (2) store prints in a dry place. Residual thiosulfate is often
> blamed, but if the RH is kept low during storage, a small amount
> (still several times higher than ANSI limits) of residual thiosulfate
> is harmless.

I agree, but a practical aspect: You can control the
process conditions include the level of fixer reminders
if You minimalize it that type of risk will also
minimalized. But probably You cannot to control the
storage conditions for the next hundreds of years. So
that You can make: prevent all risk factor as possible
while processing.

The problem with residual thiosulphate and Relative
Humidity (RH) together is the problem of the activation
energy level. More deterioration factor in the same
time can make problems even the level of each one is
relative low while eg. a relative higher hypo reminder
alone cannot hurt the silver in the same situation
(without the help of e.g. high RH and/or temperature,
light, etc.)

Naturally fiber paper is not a guarantee for forever
durability but seems like a better chance like the RC.
But we can decide it better after about 150 years :-)

Bálint

Bálint Flesch

http://archfoto.atspace.com/english.html
>
>
> From: fb <aikus2@freestart.hu>
> Subject: Re: Eastern European RC papers
> Date: Mon, 23 Jan 2006 11:37:13 +0100
>
> > Loris,
> >
> > as I wrote earlier the RC/PE papers has more risk
> > about silver degradation because soft gelatine layer
> > and the missing extra protective gel. layer. The high
> > density parts are most effective about the symptoms
> > of the deterioration because the large amount of the
> > silver. More in the case a multigrade paper that has a
> > multi silvered layer from higher speed (larger) silver
> > grains.
> >
> > The fresh fixer and normal wash is not enough usually
> > to make a durable copy on RC (anyway the RC not the
> > best material for a long term unchanged print).
> >
> > To get a good result by washing the water temp. need
> > to be higher than 20 C grade while the normal tap
> > water temp. usually lower.
> >
> > My suggestion: try to use some fixer/hypo killer before
> > endwash (the simplest 10 % sodium sulphite solution
> > but I think still there are some factory products also).
> > Some toner (sulphur, selenium, gold, etc.) and a
> > gelatine hardening bath can be good too.
> >
> > However the silver problems can be started because
> > storage conditions also (high temp., high RH, oxidous
> > gases in the air, high light/UV/IR radiation, etc.)
> >
> > Bálint Flesch
> >
> > http://archfoto.atspace.com/english.html
> >
> >
> > Date sent: Sun, 22 Jan 2006 01:41:13 +0200
> > From: Loris Medici <mail@loris.medici.name>
> > Subject: Eastern European RC papers
> > To: alt-photo-process-l@sask.usask.ca
> > Send reply to: alt-photo-process-l@sask.usask.ca
> >
> > >
> > > Let me share a recent experience with Forte RC papers:
> > >
> > > Some workprints I've made on cold tone Forte polygrade RC paper showed
> > > silver plating (metallic / reflective silver particles in the dark tones) in
> > > a relatively short time period (in about 6 months, regardless the place I've
> > > kept them. I don't know if the papers are from the same batch). I always pay
> > > extreme attention to use fresh fixer and to wash enough. This recent
> > > incident was very frustating as one of the problem prints was a gift to a
> > > friend - I printed the same image using Ziatype and gave it to my friend.
> > > Now I'm pretty sure that it won't cause any problems. :)
> >
Received on Tue Jan 24 03:42:35 2006