Noctovision - Infrared Television in 1926

John Logie Baird, besides being the inventor behind the early television system used in the UK and, arguably, being the inventor of television itself, developed several advanced versions. He was able to demonstrate large-screen, colour and stereoscopic television in the 1920s and 1930s and also developed a system for recording the images on disc ... Phonovision. In our story however, another invention of his appears: Noctovision.

Around a century ago Baird demonstrated the use of near infrared radiation as illumination for television and came up with a device he called a Noctovisor. Alexander Russell, writing in the February 5 1927 edition of Nature, described how he and WR Crookes were shown Noctovision in action at Baird's laboratory in London on December 23rd 1926.

One of us stayed in the sending room with a laboratory assistant in apparently complete darkness. In the receiving room, on another floor [of the building], the image of the assistant's head, and all the motions he made, could be readily followed.

Russell goes on to describe the images as 'not so clearly defined as when visible rays were used, but we easily recognised the figures we saw, and made out their action'.

Baird had tried ultraviolet as a means of shooting in darkness, but he found that this was damaging to the subject's eyes. His first experiments with infrared used electric fires and on one occasion a dummy actually burst into flames! His successful infrared source was an ordinary light bulb coated with ebonite to block visible radiation.

The distinguished scientist Sir Oliver Lodge (the first man to send a signal using radio) was successfully Noctovised at a meeting of the British Association held in Leeds in 1927.

Baird wrote ...

He came with his daughter and said it was 'amazing, but very hot.' I thought this was a pity, as he was the best subject for television I have ever seen, his white beard and impressive head coming through marvellously well.

Infrared video was even transmitted (by telephone wire) between Leeds and London. This was described by a journalist in London who used the link to interview Baird (who was in Leeds) as being 'like a page from the Arabian Nights tales' to be able to direct someone sitting almost 200 miles away in complete darkness and see the result on a screen instantly. It is said that the demonstration of this equipment in Leeds was so exciting that mounted police had to be called in to regulate the queues of people wanting to see it. [NB: The occasion of the Lodge demonstration was at Baird's Frith Street studio in London according to Moseley's biography of Baird. Since Moseley put it in Leeds in Television Today and Tomorrow this is a little confusing.] On another occasion, the then Prime Minister, Ramsey MacDonald, saw Noctovision and, according to Moseley, 'found it difficult to believe'.

By 1929, Baird had refined the system sufficiently for a demonstration of a self-contained infrared viewer on Box Hill in Surrey on August 9th. The device is shown in the photograph here. A simulated fog made by viewing through a thin piece of ebonite (which is opaque to visible light) was used and the Noctovisor clearly showed lights which were invisible to the unaided eye.

The authors of the description of Baird's demonstration on Box Hill, written up in a 1931 book called Television: Today and Tomorrow, were clearly excited by the naval and military possibilities. They wanted this infrared technology to provide a capability for night and fog-bound vision that was, in reality, only achieved by RADAR during World War II. Whether the Noctovisor was what we would now call a Night Vision Scope using near infrared or a Thermal Imager using far infrared is unclear in the book. However, I believe it is likely that the device was a night scope.

If this was the case then the Noctovisor would not have seen through fog as Baird intended. Near infrared will penetrate haze but as the size of the particles in the air gets larger and it becomes fog and only far infrared can penetrate.

The Baird company considered Noctovision to be a very important invention, listing it second only to television in the list of inventions in its 1928 share prospectus. Photographs of the apparatus and the demonstrations survive, but apparently not an actual Notovisor screen shot.

According to Michael Ritchie in his book on early TV (Please Stand By - see below) there was an incident at the BBC during tests with the Baird system ...

In 1933 the BBC broadcast an infrared-ray technique that 'stripped' cotton dresses off a line of dancing girls. The press teased the broadcasters about this unintended nudity. 'Scientific progress took an unforeseen turn today' wrote the London News Chronicle.

The high light levels needed by the cameras and the high infrared output of those lights (they were incandescent) also may have caused a similar incident involving a gymnast in the Soviet Union in 1938. This will no doubt bring to mind the interest shown in this aspect of infrared when Sony introduced its 'Night Shot' camcorders. The company fixed the cameras so that infrared could only work in low light levels - much to the annoyance of the 'legitimate' infrared community.

Baird's television system used a rotating mechanical disc with holes in it arranged to scan the light from a brightly-lit scene so that was 'seen' by a photo-electric cell. The 30 scan lines were vertical (this apparently looking better than a horizontal scan) and the picture was refreshed 12.5 times a second. The receiver (or monitor) had a lamp behind the scanning disc but otherwise the process just worked in reverse. An experimental broadcasting service using the London station of the BBC (call-sign 2LO) was inaugurated on September 30th 1929.

Unlike his rivals in the USA, Baird successfully synchronised the transmitted and received scans to achieve a stable picture without the motors at both ends being powered by the same synchronised AC power source. Unfortunately he is often remembered as being wedded to mechanical scanning and a film-intermediate system and eventually his system was replaced by the electronic, cathode-ray-based television we still make use of today. However the picture is more complex and Baird experimented with and even demonstrated video recording, large screen, colour and even stereoscopic television.

References

The Noctovision patents have obfuscated names which was, one assumes, to confound his rivals, but the two key ones are available on line (at least in their American incarnations).

• Method of and means for transmitting signals (US 1930, UK 1926)
• Apparatus for transmitting views or images to a distance (US 1929, UK 1926)

Television Today and Tomorrow: Sydney A Moseley and H J Barton Chapple with a foreword by John Logie Baird
Sir Isaac Pitman and Sons, London Second Edition 1931

Sydney Moseley was Baird's business manager and a tireless enthusiast for his work.

John Baird: Sydney Moseley
Odhams, London 1952 (approx)

Television for the Home: Ronald F Tiltman
Hutchinson & Co, London 1927

A very early book on the subject of television. It includes a chapter on "Seeing in Darkness", that is Noctovision.

British Television - The Formative Years: R W Burns
IEE History of Technology Series number 7
Peter Peregrinus Ltd in association with the Science Museum, London 1986

The book is expensive at £65 but the information on the technical and political background to the development of television is matchless. There is coverage of the work done in the USA, Germany, France and elsewhere as well as the UK.
ISBN 0-86341-079-0

Please Stand By - A Pre-History of Television: Michael Ritchie
The Overlook Press, Woodstock 1994

Michael Ritchie's book, refreshingly, gives an American slant on the whole business of early TV and is written in a style that is easy to read while still being authoritative. He includes the story of Philo Farnsworth, the first man to make electronic TV work (and featured, with his invention, as a character in the best-selling thriller novel Carter Beats the Devil by Glen David Gold). Although taking a programming viewpoint the book places this clearly in the context of the competitive relationship between the various elements of media big business in the US as it affected TV. How unlike the home-life of our own dear BBC!
ISBN 0-87951-546-5