Re: Updated my page with Jim Patterson Cuprotypes
Joe, Here is Jim's answer.... Hi Chris, Mike Ware's e-article, "Alternative Photography: A Conspectus", at www.mikeware.demon.co.uk/conspect.html lists the copper salt in Obernetter's Ferrocupric Process as cupric ferrocyanide. I agree. If you look at the chemistry it might seem the it should be cuprous ferricyanide, but as cuprous ion is a reducing agent, it is likely the ferricyanide is reduced to ferrocyanide and the cuprous is oxidized to cupric, just as the cyanotype pigment was argued over for a time as ferrous ferricyanide, but proved to be ferric ferrocyanide. I believe the copper salt is as permanent as cyanotype, which is considered archival by most. But I don't have any proof of that. ---- "zphoto@montana.net" <zphoto@montana.net> wrote: Christina Z. Anderson----- Message Forwarded on Sun, 11 Nov 2007 10:23:38 -0700 ----- From: Joseph Smigiel <jsmigiel@net-link.net> To: alt-photo-process-l@usask.ca Subject: Re: Updated my page with Jim Patterson Cuprotypes Date: Sun, 11 Nov 2007 12:15:03 -0500 Any idea which copper compound results to form the final image? Are these stable? Joe Assistant Professor Photo Option Coordinator Montana State University CZAphotography.com _______________ |