François Leterrier from the Association for Early Photographic Processes and their Techniques (APA) demonstrated some interesting dusting-on processes at the Eurobrom IV meeting in Paris.

Basically, in the Garnier & Salmon process paper is sensitized with  ferric ammonium citrate, dried and exposed with UV light through a positive film.

François showing an exposed paper and a positive film.

The paper is then “developed” by introducing moisture to it. Local humidity can be supplied on a small area at a time, for example by breathing on the paper. A small amount of fine powder or pigment can then be rubbed on the humid print.

Rubbing the powder on the moistened print.

“Developing” the print.

The print is then cleared by washing to remove the ferric citrate.

Clearing the print.

Another version of the process is to sensitize black paper with ferric ammonium citrate, expose it through a negative, and dust the humidified paper, using shaving brush, with ultra-fine metallic powder (powders called gold or silver are more often made with copper or aluminium).

Dusting with gold powder.

No fixing needed — ferric citrate is not visible on the black substrate, and the more the image is exposed to light, the more it is stable!

A gold powder print by François Leterrier.

More about Eurobrom to come…