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Pictures on Porcelain

The plates for these pictures are sold as porce. lain, but are really an opaque white glass. The plate is coated with collodion, rendered sensitive in the usual way, and the image received from a negative adjusted as follows:

The negative is placed at one end of a box, the other end of which joins the front end of a camera This part of the process must be conducted having a quarter tube. The object of this box is with care.

Sensitizing and Washing.

Employ 2 nitrate baths in this process, one for the collodion and the other for the second film, viz. the albumen. The albumen nitrate bath must contain free acetic acid, and therefore if one solution be employed for both films it should be a bath of aceto-nitrate.

Sensitize the collodion in the ordinary way, nolding it rather longer than usual before dipping.

Having arranged 2 dishes of common water, side by side, lay the plate face uppermost in the first dish, and wave the water backwards and forwards for about 30 seconds. Then put the plate into the second dish and leave it whilst another glass is being coated and immersed in the sensitizing bath. Now drain plate No. 1 closely on blotting-paper, and it will be ready for the iodized albumen. Plate No. 2 remains in the sensitizing bath until the first glass has been coated with albumen and placed to dry. Preparation of the Iodized Albumen.

Take of albumen, 3 oz.; distilled water, 1 oz.; strong ammonia, 10 minims; iodide of potassium, 10 grs.; bromide of ammonium, 10 grs.

First mix the ammonia and the water, then add the other ingredients and shake together in a bottle. Iodide of ammonium may be advantageously used.

To Apply the Albumen. to cut off extraneous light. The negative is placed toward the sun, or a piece of white paper placed in the sun. The image formed by the negative is focussed on the ground glass of the camera, in the usual manner. The box in front should admit of being varied in length, in order to alter the size of the picture, by changing the distance of the negative from the lens.

The white sensitive plate is then exposed and developed with the ordinary iron developer. After washing off with the developer, fix with a weak solution of cyanide of potassium.

The picture requires to be darkened with a weak solution of bichloride of mercury, chloride of gold, or chloride of platinum. As soon as the picture appears of the proper shade arrest the action of the strenghthening agent, by washing the plate under a copious stream of water.