Hurter and Driffield

  (Redirected from Hurter and Driffield Numbers)

Ferdinand Hurter (1844–1898) and Vero Charles Driffield (1848–1915) were nineteenth-century photographic scientists who brought quantitative scientific practice to photography through the methods of sensitometry and densitometry.

H & D curve used in sensitometry
Hurter & Driffield's actinograph.

Among their other innovations was a photographic exposure estimation device known as an actinograph.[1]

See alsoEdit

  • H&D speed numbers, originally described in 1890, for film speed measurements


  1. ^ William Bates Ferguson (editor) (1920). The Photographic Researches of Ferdinand Hurter & Vero C. Driffield: Being a Reprint of Their Published Papers, Together With a History of Their Early Work & a Bibliography of Later Work on the Same Subject. London: Royal Photographic Society of Great Britain.CS1 maint: extra text: authors list (link)

External linksEdit