Edward Steichen

This print of the pond on Long Island [Moonrise—Mamaroneck, New York] is held in the MoMA collection in New York. It was, from its description, made by a somewhat different process: the basis was the same – a platinotype – but after this had been completely processed, Steichen recoated the print with a cyanotype (also known as ferroprussiate or blueprint process) sensitiser and reprinted the accurately re-registered negative. This had the result of laying down an image in Prussian blue on top of the platinum image, to modify its colour and density.

(Source, including quote: platinummetalsreview.com)