Alkaline Pyro Developer.

No. 1.—Pyrogallic acid96gr.
Absolute alcohol1oz.
No. 2.—Carbonate of ammonia96gr.
Water1oz.
No. 3.—Bromide of potassium10gr.
Water1oz.

At the time of using, make up the following solution:

Water1oz.
Solution No. 110minims.
Solution No. 35”

Pour this over the wetted plate, allow it to remain on a few seconds only, and then pour back into the developing cup, and add to it 5 minims of solution No. 2, and apply again.

The Collodio-Albumen Dry Process. (Mr Mudd.) In this process the ordinary bromo-iodised collodion is employed. The plate being sensitised is washed well first with distilled, then with common water, and placed in a dish half filled with solution of iodide of potassium (3 gr. to the oz.), and allowed to remain while the next plate is being prepared. It is then removed from the solution and well washed with clean water, after which the following solution is poured over its surface:

Distilled water21⁄2oz.
White of eggs10oz.
Iodide of potassium50gr.
Bromide of ammonium10gr.
Strongest solution of ammonia120minims.

Introduce these materials with some pieces of broken glass into a bottle capable of holding twice the quantity, and agitate till the whole forms a froth, and then, when settled, it is ready. A piece of camphor placed in the solution will help to preserve it. It must be filtered before using. After the plate has been coated with the above it is finished by drying before the fire.

In this process all the above operations may be performed in ordinary white light. To render the plate sensitive, heat it as hot as the hand will bear, and when cool immerse it again in the following aceto-nitrate of silver bath for one minute, using only a yellow light, then wash thoroughly in clean water, and dry in the dark.

Nitrate of silver30gr.
Distilled water1oz.
Glacial acetic acid1⁄2dram.