There are required for this process: Some glass jars; some soft brushes, varying from the fine spotter and the Japanese brush to the 1 1/2-inch duster, and several pieces of special blotting paper.
Manipulation.—Print the paper a trifle deeper than for the ordinary method of developing. Place the print face up on a piece of clean glass (should the print curl so that it is unmanageable, moisten the glass with glycerine), and, with the broad camel’s-hair brush, thinly coat the entire print with pure glycerine, blotting same off in 3 or 4 seconds; then recoat more thickly such portions as are desired especially restrained, or the details partly or entirely eliminated. Now brush or paint such portion of the print as is first desired with solution of 1 part glycerine and 4 parts normal developer, blotting the portion being developed from time to time to avoid developing too far. Full strength developer (without glycerine) is employed where a pronounced or deep shade is wanted.
When any part of the print has reached the full development desired, blot that portion carefully with the blotter and coat with pure glycerine.
A brown effect may be obtained by using saturated solution of mercury in the developer (1 part mercury to 8 parts developer). By the use of diluted mercury the “flesh tones” are produced in portraits, etc.
When print has reached complete development, place in hydrochloric (muriatic) acid and wash as usual.
Eastman’s Sepia Paper.
Short fixing gives red tones. Longer fixing produces a brown tone.
Development Of Platinum Prints.
The Carbon Process.
The paper used is coated on one surface with a mixture of gelatin and some pigment (the color of which depends upon the color the required print is to be), and then allowed to dry. When required for printing it is sensitized by floating upon a solution of bichromate of potassium, and then again drying, in the dark this time. The process is based upon the action of light upon this film of chromatized gelatin; wherever the light reaches, the gelatin is rendered insoluble, even in hot water.