For those interested.

A simple color coating experiment:

Coat 50 mg/ft square of the Azo dye Chicago blue (or any suitable Azo dye actually, for example Tartrazine will give a yellow image). In this mix include the equivalent of 50 mg/ft square of Silver as Silver Halide. The gelatin should be at about 250 mg/ft square.

Coat on a good paper support or film with a high level of formalin hardener.

Allow to cure for up to 1 week for best hardness.

Develop in D-19 for about 1 minute.
Rinse for about 30" in running water.
Bleach in a dye bleach solution with Phenazine at about 100 mg/L and sulfuric acid to pH 1.0. until the image clears.
Rinse for about 30" in running water.
Fix in any fixer
Wash normally for a paper or film.


This should give you a positive image in color based on the chosen dye. Chicago blue will be bluish and tartrazine will be yellowish.