Re: archivalness of gum
Hey Chris,
Well, that's where you and I differ (the belief that carbon and gum
is the most archival-- instead of platinum). :) Honestly, today is
the first time I've ever heard the news that platinum isn't the most
archival. That said, the "ghosting" that you and Sandy both
mentioned-- I'm curious-- how much time does that take to occur (a
week? decades?), and under what type of circumstances, or does that
not matter? I'm also curious -- did your curator mention what he/she
believed to be the most archival?
Thanks, Chris.
Diana
On Dec 20, 2007, at 10:26 PM, Christina Z. Anderson wrote:
Judy, Gawain,Diane, etc.
Diane--platinum ghosts onto paper it is in contact with so it loses
some of its precious metal in storage I remember Dusan Stulik
telling us/showing us at an APIS. In fact, this is a method to
determine whether a print is a platinum one or not.
I was always under the assumption that carbon and gum were THE most
archival of all processes. That is why this curator's comment
surprised me so much. I have yet to come across any discussion of
degradation of gum prints except for the one article talking about
the fading of the dichromate image within the gum print. This can
be easily demoed by leaving a gum print in the sun for an
afternoon, half covered by something for comparison's sake.
Judy, gum over platinum has been done since 1902, invented by
Herbert Silberer, an Austrian.
Holland Day did it as did quite a few other Americans, and I have
never heard that wasn't archival either. In fact, one author said
the French were known for one coat gums, the Germans for multiple
coat gums, and the Americans for gum over platinum.
Gawain, I have seen some original Kuhn's at A Gallery of Fine
Photography that were perfect, and just hanging on the walls there
like no big deal. He was a master printer of the multiple gum, as
was Demachy...but the bug thing has got to be an issue and I wonder
if use of formaldehyde for hardening gelatin gives the benefit of
preserving it from bugs...oh, the cracking in the dark thing...I
wonder if sizing would contribute to that phenomenon?
So what I have deduced, after this discussion to date, is gum is
what I think it is and I wasn't whistling Dixie. I wonder if
Wilhelm has studied gum stability???
Chris
And also, by the way, gum over platinum is an historic process -- if
memory serves (which I can't promise, MEMORY is NOT archival) Paul
Anderson (heh heh) did it, but also I think Heinrich Kuhn, among
others. I
believe it was fairly well known... Then again there were many
kinds of
"platinum" including a commercial "platinum paper" -- who was the
Englishman who swore he'd stop photographing when that paper was
discontinued? He had the same name as a photo historian or other
pioneer,
but ... as noted, this memory is not archival.
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