Bromoil Print process

This process was introduced in 1907 by E.J. Wall, and consisted of a positive image on a paper support. It was based on the principle that oil and water do not mix. Once an enlargement was made, it was bleached in a solution of potassium bichromate. to remove the black silver image. This left it in a condition in which it was possible to apply greasy inks of various colours to pigment the surface of the gelatin, using special brushes. In time this replaced the gum bichromate process, which had been invented in the previous decade. Both processes, incidentally, received the term "muck spreading" by their detractors! By Dr. Robert Leggat

Information provided by: http://www.rleggat.com/photohistory/history/bromoil.htm