Judy,
Some type of toners can conservate the silver 
against degradation (gold, platinum, selenium. 
etc.) The winner (about the opinion of the big 
science) always changing. As I know the latest 
champion the sulphur toner.
Its funny because the sulphur the main silver 
killer and the main guilty in the silver 
degradation crime,
Bálint
Date sent:      	Sat, 07 Jan 2006 00:08:33 -0500 (EST)
From:           	Judy Seigel <jseigel@panix.com>
Subject:        	Re: Old Postcard Silver Patina
To:             	alt-photo-process-l@sask.usask.ca
Send reply to:  	alt-photo-process-l@sask.usask.ca
> 
> For several years I toned most of my prints with a chemical toner that 
> "plated out" silver gelatin emulsion to that silvery look, which I was 
> very very fond of.  So naturally when I found (what I called) "plating 
> out" on old photos at flea markets & photo fairs I snapped them up -- 
> usually bargains because they were considered "damaged."
> 
> These were not just, or even primarily, photo post cards, tho some of them 
> too, but all sorts of prints, from a souvenir photo of the Lincoln 
> Memorial mounted on cardboard to A.T. Bartels "Manufacturing Furrier, Fur 
> Garments of All Kinds Made To Order", shown with the staff ranked at the 
> door, undated but with the notation "Mrs. Dan Wolfe, Earlville, Ill."
> 
> In some, the "white" background has darkened to almost ochre and the 
> silvery part gotten a distinctly blue sheen, for an especially fine 
> effect.  To me, removing that patina would be error close to vandalism,
> though obviously (to quote Johnny Lock) "All men are liable to error; and 
> most men are, in many points, by passion or interest, under temptation to 
> it."  (Needless to say, if Locke had been writing in 2004 instead of 1690 
> that would have been "all persons.")
> 
> In my observation, the patina hasn't changed a lot in maybe 20 years, even 
> a few just propped up on the counter, exposed 24/7 to NYC air -- I suspect 
> the coating isn't all that reactive.  I've also seen edges of prints 
> covered by overmats which hadn't patina-ed, & therefore surmise that it 
> didn't happen, or not as readily, in the dark. (The print was under glass, 
> so I figure it wasn't primarily the air.)
> 
> On the other hand, the "Bartels" print, dark when I got it, has darkened 
> more, losing some of the shine. Tho that could be because it's glued hard 
> & fast onto black card with who knows what for paste.
> 
> Prints in those boxes of loose prints from the 1930s & later sometimes 
> show the effect, too -- but I find the effect less compelling.
> 
> Judy
Received on Sat Jan  7 01:45:24 2006
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