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Summary
Description John Logie Baird and Stooky Bill.png |
English:
British inventor
John Logie Baird
and his first publicly demonstrated television system, with which he transmitted moving pictures March 25, 1925 at the London department store Selfridges. This was one of the first demonstrations of television technology. The selenium photoelectric tubes he used had such low sensitivity that human faces could not be televised due to their low contrast. So Baird used the two articulated ventriloquist's dummies shown, "James" and "
Stooky Bill
"
(right)
, whose painted faces had higher contrast, and televised them speaking and moving. The banks of bright light bulbs were required to illuminate the faces enough to produce an image. His mechanical televisor system had a large spinning disk with 30 lenses mounted in it. As each lens passed across the subject it generated a scan line of the image. At the receiver a similar spinning disk with holes recreated the image. The image thus had a resolution of 30 scan lines, just enough to recognize a face. By the next year Baird was televising real human faces.
Caption:
BEFORE THE FOOTLIGHTS OF THE TELEVISOR TRANSMITTER - The two ventriloquist's dolls, James and Bill - "the first television stars" - are held by Baird in front of the microphone and the mechanical eye that sees and hears everything that goes on in front of it.
|
Date | |
Source | Retrieved August 15, 2014 from Orrin Dunlap, Jr., "The Televisor" in Popular Radio magazine, published by Popular Radio, Inc., New York, Vol. 10, No. 7, November 1926, p. 650 on AmericanRadioHistory.com . |
Author | Orrin Dunlap, Jr. |
Permission
( Reusing this file ) |
This 1926 issue of Popular Radio magazine would have the copyright renewed in 1954. Online page scans of the Catalog of Copyright Entries, published by the US Copyright Office can be found here. [1] Search of the Renewals for Periodicals for 1953, 1954, and 1956 show no renewal entries for Popular Radio . Therefore the magazine's copyright was not renewed and it is in the public domain. |
Other versions | The receiver Baird used with this system is shown in John Logie Baird and television receiver.jpg |
Licensing
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This work is in the
public domain
because it was published in the United States between 1929 and 1963, and although there may or may not have been a copyright notice, the
copyright was not renewed
. For further explanation, see
Commons:Hirtle chart
and
the copyright renewal logs
. Note that it may still be copyrighted in jurisdictions that do not apply the
rule of the shorter term
for US works (depending on the date of the author's death), such as Canada (70 years
p.m.a.
), Mainland China (50 years p.m.a., not Hong Kong or Macao), Germany (70 years p.m.a.), Mexico (100 years p.m.a.), Switzerland (70 years p.m.a.), and other countries with individual treaties.
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