The invention of the television was the work of many individuals in the late 19th century and early 20th century. Individuals and corporations competed in various parts of the world to deliver a device that superseded previous technology. Many were compelled to capitalize on the invention and make profit, while some wanted to change the world through visual and audio communication technology.
By the 1920s, when amplification made television practical, Scottish inventor John Logie Baird employed the Nipkow disk in his prototype video systems. He created his prototype in a little village called Santa Cruz on the island of Trinidad where he was recovering from an illness. He had also started work on the first color television. On March 25, 1925, Baird gave the first public demonstration of televised silhouette images in motion, at Selfridge’s Department Store in London. Since human faces had inadequate contrast to show up on his primitive system, he televised a talking, moving ventriloquist’s dummy named “Stooky Bill”, whose painted face had higher contrast.
By January 26, 1926 Logie Baird demonstrated the transmission of an image of a face in motion by radio. This is widely regarded as the first television demonstration in history. The subject was Baird’s business partner Oliver Hutchinson. Baird’s system used the Nipkow disk for both scanning the image and displaying it. A bright light shining through a spinning Nipkow disk set with lenses projected a bright spot of light that swept across the subject. A selenium photoelectric tube detected the light reflected from the subject and converted it into a proportional electrical signal. This was transmitted by AM radio waves to a receiver unit, where the video signal was applied to a neon light behind a second Nipkow disk rotating synchronized with the first. The brightness of the neon lamp was varied in proportion to the brightness of each spot on the image. As each hole in the disk passed by, one scan line of the image was reproduced. Baird’s disk had 30 holes, producing an image with only 30 scan lines, just enough to recognize a human face.
In 1927, Baird transmitted a signal over 438 miles (705 km) of telephone line between London and Glasgow. In 1928, Baird’s company (Baird Television Development Company/Cinema Television) broadcast the first transatlantic television signal, between London and New York, and the first shore-to-ship transmission. In 1929, he became involved in the first experimental mechanical television service in Germany. In November of the same year, Baird and Bernard Natan of Pathé established France’s first television company, Télévision-Baird-Natan. In 1931, he made the first outdoor remote broadcast, of The Derby. In 1932, he demonstrated ultra-short wave television. Baird’s mechanical system reached a peak of 240 lines of resolution on BBC television broadcasts in 1936, though the mechanical system did not scan the televised scene directly. Instead, a 17.5mm film was shot, rapidly developed and then scanned while the film was still wet. More details