To develop and then to fix the design thus obtained I wash rapidly the paper in ordinary water,

or better, in water holding chalk in suspension. The red coloration disappears, a part of the

iron perchloride is washed out, and in the parts which have not been acted on by light the

perchloride is transformed into sesquioxide. I replace then the water by solution of gallic acid or

of tannin and the image progressively appears in ink-black. When I judge the image to be

sufficiently intense I wash the proof in rain water, in preference to ordinary water, which

might cause the gallic acid and tannin to turn brown. I sponge between sheets of blotting paper

and let the proof dry spontaneously.

Pg. 43, Photographic Reproduction Processes

by P.C. Duchochois