I have made uranium prints using two different formulas with various degrees
of success.
Formula I
Sensitizer: Water 16 cc.
Uranium Nitrate 1 gm.
Developer (red-brown): Water 30 cc.
Potassium Ferricyanide 30 cc.
Wash for 10 minutes
This formula gives reddish brown prints with not much contrast if you
use a normal contrast negative. It works pretty well if you use a
higher contrast negative such as one that, if you were printing gel/silver,
you would use a no. 1 or 0 contrast filter.
Formula II
Sensitizer: Water 28.4 cc.
Ferric Ammonium Citrate 7.1 gm
Uranium Nitrate 2.37 gm
Developer: Potassium Ferricyanide 5 % (i.e. 5 gm/100 cc water)
This formula gives cyanotype-like blue tones but the contrast is good.
Some may consider this a cyanotype version, but I am not a chemist so
I cannot give an expert opinion;nevertheless, uranium is further down
on the elctrochemical series than iron I believe and therefore should
replace the iron, n'est pas?
BTW if anyone out there has any other uranium formulas, I would be
interested in them.
Finally, be VERY CAREFUL with uranium nitrate. It is radioactive, can
be absorbed through your skin and will go right to your liver, so wear
gloves and don't breath the dust.
Happy printing,
Bob Schramm