Wikipedia
Chemography is an art medium conceived by Peyton Richmond Russo ( Saint Paul, Virginia) in the early 1970s in which the artist brushes development chemicals onto sensitized photographic paper in a darkroom. It has sometimes been referred to as Chromoskedasic painting.
According to Russo, "The process is that of a painter; the materials those of the photographer. I make no use of the camera. There is no negative... In the darkroom, I brush developers onto sensitized photographic papers. My colors come from transparent oils, chemical toners or a combination of the two... Each chemograph is an original creation, an end in itself. The result is a very personal statement since it proceeds from the mind and the imagination in the isolation of the darkroom."