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.


Quote Originally Posted by davido View Post
Sandy, I didn't realize it took so long for the palladium to completely replace the silver. I would assume that a majority of the metal has been replaced after 5 minutes, would 15 minutes be needed for an archival print?
How long do you tone for?
Also, I have noticed these small stains on the back of my prints, I will try lifting the print.