[Alt-photo] A DEFINITIVE ANSWER?

[Kim Du Boise]

Hi Bob and everyone,

If you want to do the larger tray bath, PLEASE do it outside with the breeze blowing away from you…and wear something that will resemble a respirator for the gas!  Chlorine gas is nothing to sneeze at (pardon the pun), and we don't need to lose any of our talented folks.  We use (& work with) so many chemicals & combinations, and may not feel the effects of mis-handling or tight areas for years, but one day it may hurt you or cause an allergic reaction.  So be careful, please.  

Also, you should thoroughly wash the prints to get the paper back to it's stable pH, or as close as possible.  These bleaches, like the Farmer's reducer, can weaken the paper fibers if left in.

As a conservator, we work with a variety of media from ambrotypes to modern prints/films and now digital files and printing materials.  If one doesn't know what each process uses or contains, you can ruin a print, negative or positive.  

The idea of finding an equivalent compound to potassium ferricyanide for pt/pd is intriguing.  If someone wants to send scraps (& I do mean scraps or scrapped pieces of images) that we can test with various solutions, I will try to work on it.  If someone has already started or tried this, please send me info as a starting point & why it did not work.  

I would need to have enough to cut into at least half or more sections to test out solution strengths.   I will even try with dark spots.  Just let me know the number of coatings, sized or not, and any other information you feel is relevant to investigation.  Scraps will be cut & examined to see how deeply the emulsion goes into the paper; it may be too deep to bleach well.  

If anyone wants to try this, I am game and will post anything we find out (good or not) for all to see.  Just remember, we are a conservation lab and this is my day job…so it may be that this will take a bit of time to get info back to the list.    

All the best,
Kim

Kim R. Du Boise, P. A. - AIC
Senior Conservator
PhotoArts Imaging Professionals, LLC
123 Buchanan Road
Hattiesburg, MS  39401-9545

Local:	601-582-3686
FAX:	601-544-1920
Toll-free:   866-278-3686
www.photoartsimaging.com