Portrait of two Indian Hockey players; Tudor Washington Collins; 1955; Silver gelatin dry plate. Photograph: Auckland War Memorial Museum, Wikimedia Commons

A method of producing photographic negatives that emerged in the 1880s, using a glass plate coated with silver salts in a stable gelatin base. Offering portability and light-sensitivity long after the base is prepared, this technique replaced the collodion wet plate method and forms the chemical basis for most modern analog photography.