Shelford Bidwell Biography – Inventor of Telephotography

Last Update: August 9th, 2021

Shelford Bidwell (6 March 1848 – 18 December 1909) was known as an English physicist and inventor. His most famous work was in the field of “telephotography,” one of a few inventions that have evolved into today’s facsimile machine.

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Born in Thetford, Norfolk, the oldest son of a brewer, he graduated from Cambridge. He was called to the bar from Lincoln’s Inn in 1873.

After practicing as a barrister for a number of years, he became interested in electronics.

Research and Invention

Bidwell’s research was primarily in the areas of tele-photography – the ability to transmit an image over infrastructures such as telegraph and telephone lines.

In early experiments, Bidwell as able to duplicate the “photophone” created by Alexander Graham Bell.

Using sound to vibrate a mirror, the vibrations were captured by a selenium photocell that was connected to a telephone, converting the light into an electrical signal.

In the area of facsimile, Bidwell‘s best-known experiment involved a selenium photocell placed inside of a rotating cylinder.

A small hole was placed on the cylinder that permitted the photocell to be able to scan an image that was placed on a brightly illuminated glass slide. A receiving cylinder was covered with paper impregnated with potassium iodide.

The invention worked by sending an electrical signal from the photosignal to a platinum wire that darkened the paper with current was applied to it.

In many senses, it was a similar result to Alexander Bain and Frederick Bakewell‘s inventions, however, occurred with a completely different process. As well, it suffered from the same challenge of properly synchronizing the sending and receiving terminals.

The results were introduced by Bidwell in an article called “Tele-Photography” in the February 1881 edition of Nature.

Today his telephotography device is displayed in the London Science Museum.

In the June 1908 edition of Nature, Bidwell commented on recent developments in “telegraphic photography” by others in the scientific community. As well, he was one of the first to calculate the transmission “bandwidth” required to send images electronically, theorizing on different circuits or wires at a time far before the invention of modern day networks and computer systems.

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