L Liesegang's Process 1865
Pour ammonia into a nitrate of uranium solution, wash the precipitate of
uranate of ammonia in distilled water, then dissolve in citric acid.
Mix this solution of citrate of uranium and a little of a solution of
chloride of gold with a paste prepared by dissolving tapioca in hot water.
The quantity of chloride of gold must be small and the heat not too great,
otherwise the gold would be reduced.
Spread the mixture with a sponge on the paper, which takes a brilliant
yellow color, and expose when quite dry; the proofs have the delicacy and
vigor of albumen prints.
The proofs come from the frame with a bluish-black color; they should not
be toned, but merely fixed by washing until the yellow color of the paper
The color of the picture can be changed to a purple by a solution of
chloride of tin.