1A print produced by the platinotype process.
2An early photographic process producing prints in platinum black, using paper coated with a solution of potassium chloroplatinite, K ₂ PtCl ₄, and ferric oxalate, and developed in hot potassium oxalate solution. Usually attributive.
Mid 19th century; earliest use found in Robert Hunt (1807–1887), chemist and photographer. From platinum + -o- + -type.