X'S PROCESS (1865). (Secrets of the Uranotype)

Preparation of the Uranium Compound.—Precipitate the nitrate of uranium from its solution by concentrated liquid ammonia. Let settle the precipitate, decant, and wash in several changes of water. Dissolve it by heat in pure nitric acid, taking care not to add an excess of acid. The ammonio-nitrate of uranium salt is then crystallized and dried. Mix a solution of 6 drams of this salt, dissolved in 3 drams of water, to a solution of 15 grains of silver in 30 minims of water, and crystallize. This salt is called ammonio-nitrate of uranium and silver.

SENSITIZING SOLUTION.
Ammonio nitrate salt3 drams
Alcohol8 drams
Distilled water15 drops
Nitric acid, pure1 drop

Plain Collodion.—Dissolve in a small quantity of ether 1 dram of Canada balsam and 1 dram of castor oil, filter and let evaporate the solution to the consistency of oil.

Of this, add 10 minims to a collodion made of

Alcohol10 ounces
Ether20 ounces
Pyroxyline220 grains
SENSITIVE COLLODION
Plain collodion12 drams
Sensitizing solution6 drams
Nitric acid2 or more drops

Keep this collodion in the dark, as it is quite sensitive.

PREPARATION OF THE PAPER
Arrowroot, pulverized1 ounce
Water32 ounces
Solution of acetate of lead10 drops

Heat to 100 deg. Fahr. and then add four ounces of albumen. The paper is floated on this solution for five minutes and hung up to dry. The sizing may also be applied with a sponge in the manner often described.

The proofs should be slightly over-printed and, before toning and fixing, placed for about ten minutes in the following solution:

Distilled water40 ounces
Acetic acid1 ounce
Hydrochloric acid1 ounce

After washing in several changes of water, the proofs may be toned in any toning bath, and then fixed with sulphocyanide of potassium, washing afterwards in the usual manner.