The first commercially exploitable method of producing a photographic print on paper from a negative. It used the albumen found in egg whites to bind the photographic chemicals to the paper. The process was invented in the mid-19th century by Louis Blanquart-Evrard (1802-1872) and became the dominant technique of photo printing from 1855 to the turn of the 20th century. Video here.
John Robert Parsons. Jane Morris. 1865. Albumen print.