Thanks, Sandy. When I refer to platinum prints, I'm including palladium in that, so-- as you say-- they are both more stable than gold. I was/am aware that metals are classified, and I was somewhat familiar with their ranking or ordering, but I did not know that graphite was #1 in that ordering. I always thought graphite was a soft mineral (?), which, for me, equates with weak (not strong, and therefore, not stable??). That's my logic, anyway, so this is really interesting.
I now have to revise my line about platinum/palladium prints, to simply say "one of the most archival . . . " which doesn't seem to have the same impact. I don't think I'll ever learn carbon printing, at least not in this lifetime, but good to know this (and about gum).
Thanks Sandy, and Marek.
Diana
On Dec 20, 2007, at 2:33 PM, Sandy King wrote: Diana,
Metals are classified by a scale known as the galvanic series, which determines the nobility of metals and other substances such as graphite (graphite is actually a polymorph, as is a diamond, of the element carbon). According to the galvanic series, the order is 1) graphite, 2) palladium, 3) platinum, 4) gold, 5) silver, 6)titanium and so on to the stainless steels and bronzes.
So it is true that platinum is more stable than gold, but palladium is more stable than platinum, and carbon is more stable than palladium, platinum and gold.
Many people have observed that when a platinum print remains in contact for a long period with covering piece of paper there may be a partial transfer of the image from the original print to the other paper. To my knowledge this has not been observed with gum or carbon prints.
Sandy
At 2:14 PM -0500 12/20/07, Diana Bloomfield wrote: Well, I was told at one time that platinum is more stable than gold-- consequently, at least one of the reasons it's the most archival. (The other reason is probably that it's so ridiculously expensive that we have to convince ourselves that it has to be the most archival, if not the most beautiful, in order to justify the cost.) Whatever-- I'm thinking I'll still go with the platinum-is-more-stable-than-gold story whenever some museum curator asks me that question-- that is, until I learn carbon printing, or perfect gum printing. :)
Diana
On Dec 20, 2007, at 1:27 PM, Sandy King wrote:
Diana,
In fact gum (and carbon also) are probably more permanent than platinum, assuming one uses light fast pigments. Carbon pigment is totally inert, and a print that consists of carbon pigment in a hardened layer of gum arabic or gelatin would be limited in terms of life more by the support on which the print is placed than the image itself.
Sandy King
At 12:03 PM -0500 12/20/07, Diana Bloomfield wrote:
Hey Chris-- Isn't platinum the most archival process? At least, that's what I always tell people. I'm sure I read that somewhere. I did have someone ask me an interesting question recently that I never thought to ask anybody-- but I had made a gum over platinum print, and this person suggested that by using gum over the platinum, I was harming the platinum in some way-- or, at least, somehow removing the archival nature of the platinum, since-- this person said-- gum isn't archival. I think this person was only *assuming* that gum isn't archival-- really didn't know for sure-- but I thought it was an interesting question.
On Dec 20, 2007, at 10:30 AM, Christina Z. Anderson wrote:
Good morning all!
This may be a question for Gawain Weaver as I don't know who else on the list is "in the know".
I have always read/thought/been told that gum along with carbon is the most archival process there is.
I heard a comment the other day from a museum curator who said it was "not the most archival process".
Now, I know that certain pigments used in the past were NOT lightfast. Gamboge, alizarin crimson, etc. were pigments that faded thru time we now know and the watercolor painters know, too. Also, I know that if you leave the dichromate stain in as a darker brown addition underneath the gum layer, through time in sunlight that image will fade to gossamer green and therefore the print will lighten **somewhat** (found a cute little article on that fact about gum prints "fading on the walls of exhibitions"). But if using archival pigments and also taking into account the slight tone difference of an added dichromate stain now that we are not cooking our prints with heavy 100% sodium dichromates, etc.,, aren't gum prints really archival?? Anyone have gum prints that have not lasted? I've seen Kuehn's and Demachy's but unfortunately, photography is a relatively new art and thus we only have about 170 years of evidence.
Unfortunately, I left my only conservation book (thanks, Gawain) at home and I am in FL for 3 wk--writing my gum book at least!
Chris
Christina Z. Anderson
Assistant Professor
Photo Option Coordinator
Montana State University
Box 173350
Bozeman, MT 59717
406.994.6219
CZAphotography.com
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