light sources must be used and exposure times are many times greater than those used in silver-based photographic processes. Due to the unavailability of pre-coated sensitized paper, all platinum/palladium printing is done on paper coated by the printer. The light sensitive chemicals are mixed from powdered basic chemicals, or some commercially available solutions, then hand applied with a brush or a cylindrical "pusher". Many artists achieve varying effects by choosing different papers for different surface characteristics, including vellum, 100% cotton rag, silk, and rice, among others. On the collecting market, platinum prints often sell for many times what a similar silver-gelatin print would bring. Notable photographers using the technique Dick Arentz David Bailey George Charles Beresford Manuel Álvarez Bravo Alvin Langdon Coburn Lois Conner Imogen Cunningham Edward S. Curtis F. Holland Day Dazeley Frederick H. Evans Laura Gilpin Naohisa Hara Frederick Hollyer Gertrude Kasebier David Michael Kennedy Sal Lopes Robert Mapplethorpe Andrea Modica Tina Modotti Isabel Muñoz Irving Penn Ted Preuss Sebastiao Salgado Tom Sandberg J. Shimon & J. Lindemann Edward Steichen Alfred Stieglitz Paul Strand George A. Tice Robert Vano Edward Weston Clarence H. White Trevor and Faye Yerbury See also Photographic processes References Further reading Dick Arentz. Platinum & Palladium Printing, Second Edition. Focal Press. 2004 External links Photographic processes dating from the 19th century Alternative photographic processes