Quote Originally Posted by Ole
Most silver-bearing contact-print versions can be bleached just as effectively - but somewhat slower and thus (IMO) safer in very dilute rapid fixer. Opens up the midtones without losing highlight detail. Works great on POP and van Dykes, at least.
The concern I would have about this for kallitype is the fact that it works. What I try to achieve in toning is a print that will be as permanent as possible. The action of bleaching is in some ways a very much accelerated process of again. With silver printing you have some built-in protction of the silver metal from the gelatin within which it is encapsulated. With kallitype all that metal is right on the surface and extremely vulnerable to attack by the elements. For that reason most everyone recommends toning kallitypes, and one measure of how effective the toining has been is how resistant the print is to bleaching.

I am quite surprised that there was so much bleching after gold toning. With palladium toning a kallitype print will bleach back no more than 2-5%, and this will be in the shadows. Gold toning should be at least as effective as toning with palladium.