From: Sandy King (sanking@clemson.edu)
Date: 10/29/03-10:48:07 PM Z
OK, I ran the the ferri+bromide bleach test with a palladium toned
kallitype. For the test I used the Kodak R-14 formula, diluted One
Part A + 15 Parts B + 150 Parts Water to bleach the 4X5" tests.
The four tests themselves were toned for 10 minutes each with
different strength toners, ranging from 2.5ml to 10ml of a 20%
palladium solution per liter of toner. All of the prints were toned
with 10ml of the working toning solution. As you can see, the print
with the strongest toner used about 0.1ml of the 20% palladium. By
contrast I need about 0.5ml of the 20% solution to make a straight
palladium print.
All of the prints were bleached for 10 minutes each, after I
determined that this was the time needed to completely bleach out the
image of an untoned kallitype . The amount of density lost in
bleaching ranged from a lot for the one toned in the weakest toning
solution to very little for the one toned in the strongest solution.
Regarding the print that was toned in the strongest toning solution
(10ml of a 20% palladium solution per liter of toner), the measured
reflective density before bleaching was 1.42, and after bleaching it
was 1.36. This means that the palladium in the print, whatever its
form, was contributing about 96% of the total density of the print
before bleaching, with 4% coming from the silver. This is actually
quite a bit higher than I anticipated after hearing of the results of
Etienne with other processes.
What I gather from this test is that a palladium toned kallitype
should have great permanence since virtually all of the silver has
been replaced with palladium. However, since a very small percentage
of the silver remains in the print I will continue to call my prints
of this type as palladium toned silver-iron prints, not just
palladiums, even though for all practical purposes they are *almost*
that.
Sandy
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