cshimokita
[Photo Forum Moderator]
10714
Hurter & Driffield... Actinograph
In 1888, Ferdinand Hurter and Vero Charles Driffield patented the "Actinograph", a device for computing exposure times and apertures for cameras. It didn't measure anything, and was more like a slide rule based on the plate speed, time of day, time of year, and latitude.
Hurter & Driffield are noted for their work in sensitometry, the scientific study of light-sensitive materials. Plots of film density (log of opacity) versus the log of exposure are called characteristic curves or HD curves, named after Hurter & Driffield.
Thanks for looking,
Casey
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Actinograph Photo Credit: Public Domain
Hurter & Driffield... Actinograph
In 1888, Ferdinand Hurter and Vero Charles Driffield patented the "Actinograph", a device for computing exposure times and apertures for cameras. It didn't measure anything, and was more like a slide rule based on the plate speed, time of day, time of yea...
The Latitude on the H-D graph is...
54º 30' 0" N... e.g. the Lake District, Cumbria in northwest England
Don't you just love history...
Marion & Co. of Soho Square, London, and of Paris, maker of cameras, plates and papers and general photographic requirements was established in the 1840s by Auguste Marion. 1921 - Amalgamated Photographic Manufacturers Ltd was formed by merging seven Brit...
Great idea... they put a man on the moon using slide rule...
I still have mine from the 60s... haven't used it in 40 years. I did pick up a scientific calculator a couple of years ago... so useful ; ) Casey
