(a) Pour 20 oz. boiling water on 100 gr. ammonium chloride and 60 gr. Iceland moss. When nearly cold, filter, and immerse the silk in it for 15 minutes. To sensitise, immerse the silk in a 20-gr. solution of silver nitrate for 16 minutes. Let the nitrate bath be rather acid. When dry, prepare for printing by attaching the silk to a piece of cardboard a little smaller than itself, by turning the edges over and fastening with small pieces of gummed paper. Slightly over-print. Wash in 2 or 3 changes of water, and tone in a gold bath made thus - 29 oz. water, 2 dr. soda acetate, 4 gr. gold chloride, and a few gr. common whiting. Filter and keep for 24 hours before using. Let the prints be toned slightly bluer than they are required to be when finished. Rinse them in water, and fix in a solution of hypo., 4 oz. to the pint of water; 20 minutes is ample time for fixing. Wash well.

(6) Dissolve by soaking for about 6 hours, and afterwards gently heating, 10 gr. fine white gelatine in 20 oz. water, and when solution is complete add 45 gr. ammonium chloride; filter and label No. 1. Make No. 2 solution of silver nitrate 300 gr., citric acid 3 gr., water 10 oz., filtering as usual. To sensitise the silk, coyer it first with No. 1 solution, and after that has dried, with No. 2. A sufficient quantity of No. 1 to completely coat the silk having been poured on, it is spread over the entire surface by means of a canton flannel swab, and is allowed to remain on the silk about two minutes, after which the surplus is removed and the frame is set aside to dry in a place free from dust. The No. 2 solution is then applied in the same manner for about 2 minutes, except that the operation must be performed in a dark or dimly-lighted room. Before printing, the silk is drawn tight over a stretcher, care being taken to remove all wrinkles and to secure a perfectly flat surface. The negative is then placed in the printing frame, and upon it the silk stretcher.

The printing, toning, and fixing are accomplished in the ordinary way, except that the print is a little darker than on silvered paper, and toned to a somewhat colder colour, (c) Make the following solutions: -

No. 1. Tannin .. .. 40 grm. Water .. .. 1000 cc.

No. 2. Salt- .. .. 40 grm. Arrowroot .. 40 grin. Acetic acid ..150 cc. Water .. .. 1000 cc.

No. 1 is mixed with No. 2, well shaken, and filterel. The older the mixture, the better it is for use. In this bath the silk is thoroughly immersed, and allowed to remain for 3 minutes, when it is taken out and hung up to dry.

Sensitising solution is composed of silver 1 to 10 grm., acidified with nitric acid.

Toning Bath.

No. 1. Gold chloride ...... l grm Water.......... 200 cc.

No. 2. Ammonium sulphocyanide .. 20 grm. Water...... .... 500 cc.

No. 1, after shaking, is mixed with No. 2. In a few days the mixture will become clear, when it is ready for use. It is preferable to dilute with 2-4 times the quantity of water. Fixing and washing as usual.