What is Palladium Printing ?

For the negative printing buff, here's David Michael Kennedy's definition of what Palladium Printing is all about:

In the palladium process, fine art paper is sensitized with a mixture of ferric oxalate, potassium chlorate (which increases contrast) and sodium chloropalladite (palladium and salt).

The sensitizing is accomplished by pouring the sensitized solution (emulsion) onto the paper and then brushing it on evenly with a fine brush. Depending on the desired look and depth of the final print, you may use one or two coatings of the emulsion. After drying, the print is exposed in direct contact to the negative by either sunlight or a strong ultraviolet source. It may be developed in a variety of chemicals depending upon the desired warmth of the final print. I use a saturated solution of potassium oxalate heated to about 120 degrees. That gives the image a great deal of warmth.

Exposing the ferric salts to light reduces them to the ferrous state. When the print is placed in the developing solution, the new ferrous salts are dissolved and reduce the palladium to the metallic state.

The print is then cleared in hydrochloric acid or other citric acids to eliminate the remaining ferric salts in the paper. The image that is left consists of metallic palladium in a finally divided state.

The print is then washed for 30 minutes and air dried. Other than the obvious beauty of the process and the truly archival quality, what intrigues me is that each print is different.

In an edition of 10 to 20 prints each will have it's own subtleties that make it unique from the others.