[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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