U of S | Mailing List Archive | alt-photo-process-l | archivalness of gum

archivalness of gum

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!
Christina Z. Anderson
Assistant Professor
Photo Option Coordinator
Montana State University
Box 173350
Bozeman, MT  59717