Hurter & Driffield

H&D curve in sensitometry

Ferdinand Hurter (1844–1898) and Vero Charles Driffield (1848–1915) were 19th century scientists in the field of photography. They studied photography quantitatively and used methods of sensitometry and densitometry .

Actinograph according to Hurter & Driffield.

One of their inventions was a device with which one could estimate the exposure parameters, the "actinograph".

Among other things, they investigated non-linearities with very short and very long exposure times.

A unit for determining the film speed of photographic plates, H&D, was named after them.

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1. ^ William Bates Ferguson (Editor): 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, 1920.
2. ↑ Erna Padelt, Hansgeorg Laporte: Units and sizes of the natural sciences . Fachbuchverlag Leipzig, 1967 (under Scheiner: "Identification of the sensitivity to light of photographic plates (see Table 57)." In the table there are conversions from DIN to ASA, GOST, Scheiner and H&D).

• Ron Callender: Encyclopedia of Nineteenth-Century Photography . 2008, pp. 732–4 ( A Brief History of Hurter & Driffield ).