One way to check this for those who have access to the equipment is to look
at the photo in a scanning electron microscope with an energy dispersive
x-ray spectrometer. These are quite common in universities. Provided that
the print is not too large to fit in the vacuum chamber one can analyse the
metal component of the image in a non destructive way. I tried this with a
small print that I thought was a palladium print. I didn't find any Pd but
I did find silver and iron. The print doesn't look like a silver gelatin
print so I had to conclude that it was a Kallitype due to the fact that the
image appears to be in the paper and the small amount of iron present from
the sensitizer. I would guess that the print was probably made pre WWII.
If my conclusion is correct about it being a Kallitype then it has survived
quite well since I see no signs of fading.
--------------------------------------------------------
John Hudak hudakjm@mcmaster.ca
Electron Optics
Brockhouse Institute for Materials Research
McMaster University
Hamilton, Ontario, Canada