The technique is based on the late 19th century sensitometry studies of Hurter and Driffield. The primary authority on the design of the film was concept artist Albert Hurter. The narrator meets Miss Hurter, an American admirer of the writer's, in his house. Hurter and Driffield began pioneering work on the light sensitivity of photographic emulsions in 1876. In 1867 Deacon took on a chemist, Ferdinand Hurter, on a month's probation. The Society of Chemical Industry endowed the Hurter Memorial Lecture in his name. In time Hurter was to become the chief chemist to the company. Hurter campaigned for free education and for the introduction of the metric system into Britain.