One of the conservators at the Getty Museum in LA tested four kallitype prints that I processed identically except for length of toning time. I posted the results at the time on the alt photo process list but have since misplaced the data. However, my recollection is that replacement was about 60% at five minutes, 70% at ten minutes, 80% at 15 minutes and 90% at 20 minutes.
Those figures are probably off a bit, but what you see is that with this toner it would take a fairly long time to replace all the silver. However, even if only 80-90% of the silver is replaced with palladium the print should be quite archival by any standard.
Originally Posted by davido