This process dates from 1873, when it was introduced by William Willis. Plain paper with sensitive iron salts (no silver) was exposed in contact with a negative. The print would then be developed in a potassium oxalate solution.
The process produced an image with beautifully rich black tones, and a tremendous tonal range, that makes platinum prints stand out. It was also, unlike other processes, permanent.
Amongst those who used this medium were Peter Henry Emerson, Clarence White , Frederick Evans, and Gertrude Kasebier.
One of the reasons why this and the gum-bichromate process became more popular amongst serious photographers was that these were ways of distancing themselves from the snapshooters which began to proliferate as a result of the introduction of the first Kodak cameras and film; both processes required skills above the level of the casual amateur photographer.
Its use declined after the first world war because of the rising cost of platinum, when palladium largely replaced it.
© Robert Leggat, 1997.