[pure-silver] Re: Any news from Ilford?
- From: "Dave Valvo" <dvalvo@xxxxxxxxxxxxxxxx>
- To: <pure-silver@xxxxxxxxxxxxx>
- Date: Fri, 28 Jan 2005 08:53:48 -0800
Hi Richard,
First, as you know, the problem will only occur in papers with ID.
Second it will not happen with any Kodak papers. (I don't know about Agfa
but I think they were protected as well.)
The effect is dependant on how old the papers were BEFORE they were
processed. The older the paper the longer ID had to migrate through
the resin.
Storage conditions after processing are of no consequence except I expect
higher temperatures will accelerate the effect.
The worst Ilford paper was Ilfospeed Rapid RC. I recall it had the highest
ID slug. Discontinued many years ago..... was designed for newspapers.
Dave
----- Original Message -----
From: "Richard Knoppow" <dickburk@xxxxxxxxxxxxx>
To: <pure-silver@xxxxxxxxxxxxx>
Sent: Thursday, January 27, 2005 11:08 PM
Subject: [pure-silver] Re: Any news from Ilford?
>
> ----- Original Message -----
> From: "Dave Valvo" <dvalvo@xxxxxxxxxxxxxxxx>
> To: <pure-silver@xxxxxxxxxxxxx>
> Sent: Thursday, January 27, 2005 11:18 PM
> Subject: [pure-silver] Re: Any news from Ilford?
>
>
> > Richard, the truth is that Ilford RC papers with a full
> > slug of ID would
> > degrade within 6 months of processing. What happens is
> > the ID is not locked
> > into the emulsion. It leaches through the resin layer
> > into the paper fibers
> > as it sits in the box before processing. After
> > processing, the ID within
> > the paper begins to oxidize and turns a pinky color with
> > increased Dmin
> > visible from both sides. Kodak RC papers never had this
> > problem because
> > their paper fibers contain antioxidants to neutralize any
> > ID that migrates.
> > Thus Ilford, with Deluxe paper, removed most of their ID
> > from their paper
> > but left a little in for shelf life pre-process stability.
> > You should be
> > able to detect it with the carbonate solution (high pH)
> > Ryuji suggests.
> > Some natural age tests I have run on Ilford Deluxe RC
> > papers show the defect
> > is still there but to a much, much lesser extent and it
> > takes a longer time
> > to be visible.
> >
> >
> > Dave
> >
> I have old (about ten to fifteen years) Kodak and Agfa RC
> prints which do not show this degradation. I don't see it on
> old Ilford papers either but don't know for certain which,
> if any, had DI in them. The one paper I do see the
> pink-brown discoloration is Arista, which is Kentmere in
> disguise. Again, I don't know if it was DI or not.
>
> ---
> Richard Knoppow
> Los Angeles, CA, USA
> dickburk@xxxxxxxxxxxxx
>
>
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