[rollei_list] OT: Selenium accuracy was: Re: Re: An ebay explanation
- From: Aaron Reece <oboeaaron@xxxxxxx>
- To: rollei_list@xxxxxxxxxxxxx
- Date: Mon, 19 Mar 2007 17:22:34 -0400
On Mar 19, 2007, at 1:42 PM, marcsmall@xxxxxxxxxxx wrote:
It is one of the great myths of photography that selenium is
inherently inaccurate.
Indeed; my all-time favorite application of selenium-cell technology
has to be G.E.'s Pallotrope, an optical microphone originally
designed to record audio onto motion-picture film. The Brunswick
recording company used it to make several recordings starting in 1925
when they couldn't get access to the Western Electric electric
recording technology which Victor and Columbia had licensed.
The Pallotrope worked by suspending a tiny crystal mirror inside an
acoustic recording horn and shining a beam of light at it; as the
sound vibrations shook the mirror, the reflected light beam was
modulated and the resulting modulation registered on a selenium cell
which converted the fluctuations in light intensity to fluctuations
of voltage. While the audio signals thus produced were inferior to
contemporary electric recordings, there is a certain evil genius to
the concept. I believe Brunswick shelved the system after a brief
time (about a year).
-Aaron
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