RE: Old Postcard Silver Patina

DEAR LIST,
        Forgive my "Bobby come lately" entrance into this thread but I just caught
up on reading my e-mails. Isn't the effect all of you have described
referred to as "dichroic fog" and is the result of not using an acid stop
bath (either going from dev straight into fix or using a water rinse w/o
acetic acid to reduce the pH) and using an acid fixer? It appears that
there is some reaction that results from putting a print which is still
alkaline from the developer into an acid fixer. I have been told that this
isn't a problem when using ammonium thiosulfate fixers which are of a higher
pH. Ryuji, can you comment on this?
I have been told by conservators that it isn't visible until after some
time. I recall seeing some lovely
2 1/4 X 3 1/4 contact prints of NYC buildings by Bernice Abbot which had
this "silvering" in the shadows.
                        CHEERS!
                                BOB

 Please check my website: http://www.bobkiss.com/

-----Original Message-----
From: fb [mailto:aikus2@freestart.hu]
Sent: Saturday, January 07, 2006 3:45 AM
To: alt-photo-process-l@sask.usask.ca
Subject: Re: Old Postcard Silver Patina

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 05:36:15 2006