Well-sized paper is employed. If the sizing should be insufficient, resizing can be done with a 10 per cent gelatin solution, with a 2 per cent arrowroot paste, or with a 50 per cent decoction of carrageen. This size is applied on the crude paper with a brush and allowed to dry. The well-sized or resized papers are superior and the picture becomes stronger on them than on insufficiently sized paper. Coat this paper uniformly with a solution of 154 grains of ferric oxalate in 3.5 fluidounces of distilled water, using a brush, and allow to dry. Next, apply the solution of 15.5 grains of silver nitrate in 3.5 fluidounces of water with a second brush, and dry again. Coating and drying must be conducted with ruby light or in the dark.

The finished paper keeps several days. Print deep so as to obtain a strong picture and develop in the following bath:

Distilled water.. . 3.5 fluidounces

Potassium oxalate (neutral) .. 340 grains

Oxalic acid..... 4 grains

After developing the well-washed prints, fix them preferably in the following bath:

Distilled water.. 3.5 fluidounces

Sodium thiosulphate........ 75 grains

Gold chloride solution (1 in 100)......... 80 minims

Any other good bath may be employed.


Starch is dissolved in water and the solution is boiled until it forms a thin paste. Carmine powder is added, and the mixture is rapidly and assiduously stirred until it is homogeneous throughout. It is now poured through muslin and spread by means of a suitable pencil on the paper to be sensitized. Let dry, then float it, prepared side down on a solution of potassium chromate, 30 parts in 520 parts of distilled water, being careful to prevent any of the liquid from getting on the back or reverse side. Dry in the dark room, and preserve in darkness. When desired for use lay the negative on the face of the paper, and expose to the full sunlight for 5 or 6 minutes (or about an hour in diffused light). Washing in plenty of water completes the process.