Alan writes ... As both creators and watchers of video / TV productions, we should all be grateful to the man who started it all. Inevitably, there is some dispute over who exactly did what, when it came to inventing television, but there is no doubt about the man who deserves most of the credit; John Logie Baird, who was born in 1888 and grew up in Scotland. Whilst at college, Baird undertook a series of engineering apprentice jobs, but his degree course was interrupted by the First World War. He never returned to graduate. He volunteered for service in the British Army but was declared unfit for active duty. Instead, he took a job with the Clyde Valley Electrical Power Company.
Having become interested in the possibility of transmitting moving pictures electronically, he started to investigate the possibility of using a device known as the Nipkow disc. This is a disc containing a series of holes which when spun in front of a lamp, traces out a series of adjacent, curved light beams. Baird realised that it could form the basis for his mechanical television system. He substantially improved the concept, and was soon able to make the first trials of his new system. The subject was placed in a darkened room, and the beam of light scanned across them. A photoelectric cell gathered the reflected light and an amplified signal was sent to lamp which, with a second scanning device, projected a light beam that moved in synchronism with the first. And, lo, television was born!
In October 1925, Baird successfully transmitted the first television picture with a greyscale image: the head of a ventriloquist's dummy.
It was a 30-line, image, at five pictures per second (frames per second, in today’s parlance). Compare this with our current standard of at least 625 or 1080 lines, and a frame rate of 50 per second.
Having the subject sit in a darkened room was obviously quite a limitation, so Baird soon moved to a system where conventional film was used to capture the image. After very rapid development of the film, it was immediately scanned by a device, based on a Nipkow disc, to provide the electronic TV signal. Not very practical!
To promote his system, Baird called at the Daily Express office, to seek publicity. Allegedly, the news editor was rather worried and said to his assistant "For God's sake, go down to reception and get rid of a lunatic who's down there. He says he's got a machine for seeing by wireless! Watch him - he may have a razor."
In January 1926, Baird repeated the demonstration of his TV transmission for members of the Royal Institution. This time he increased the frame rate to 12.5 pictures per second. It was the first demonstration of a television system that could scan and display live moving images with full tonal graduation. He then worked with the BBC to transmit these images across the airwaves to people’s homes. In 1927, Baird transmitted a long-distance television signal over 705 km, by telephone. The device worked, after a fashion, but still had serious limitations. At about the same time, the fully electronic Marconi-EMI television (the forerunner of today’s TV) was coming to fruition, and would prove to be much more practical for commercialisation.
Baird was a determined man, however, and persuaded the BBC to run test transmissions, from London’s Alexandra Palace, using both his mechanical system (now with 240 lines) and the EMI 405-line electronic alternative. It soon became apparent that the EMI system was far superior and, in 1936, the BBC selected this system over Baird’s for the World’s first television broadcasting. Although Baird’s mechanical TV proved to be a blind alley, he must be credited with having promoted the idea of transmitting moving images, in the face of much scepticism. And, he did much, much more, including inventions that are familiar to us today. He demonstrated the world's first colour transmission in 1928, using scanning discs at the transmitting and receiving ends with filters of each different primary colour.
In 1941, he demonstrated a system of three-dimensional television with a definition of 500 lines. Between 1926-1928, he worked on an early video recording device, called Phonovision, consisting of a large Nipkow scanning disk attached to a record-cutting lathe. It gave a disc that could record a 30-line video signal. Not quite a match for our BluRay discs, but thanks, Baird, for all your great ideas.