The Dawn of Television

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hirty years before videotape Fig, l, Resembling recording, between 1927 and contemporary audio 1928. John Logie Baird experi- discs, these are the mented with recording his television different types of discs signal onto discs. Five years later, that contain the enthusiasts made a few off-air disc worl{s earliest-known recordings of the BBC's 30-line tv recordings of broadcasts. The discs have remained as television. curiosities since then, defuing attempts to retrieve recognisable pictures. For many years I have been seeking out and restoring these discs using software signal and image processing. The filming a television display - was the images recovered from the discs give a only method of capturing the fleeting remarkable insight into those pioneer- images. Broadcast companies used the ing days of tv. As a bonus, analysing technique widely and for many years the recorded signal and its distortions after the intoduction ofvideotape. The unfolds a wealth of new information quality, however, was always poorer on the mechanical tv era. than the original material largely because it had the extra distortion Recorded live... incurred by being displayed and In television's short history, the filmed. development of video recording technology has lagged behind broadcast The first recordings? television by decades. In 1956, Ampex The earliest direct video recordings in the USA demonstrated and market- appear to come from Ampex's video ed the world's first practical broadcast recorder between 195l-56, or the video recorder. I It was one of the great technological achievements of the television age and transformed broadcast Fig. 2. A single spiral 30-line Nipkow television services, rapidly becoming lens disc set up for the Baird essential to programme production. standard, The area for imaging or Before videotape,'tele-recording' - display is shown in green, For a l,5m diameter disc, this area is only about *Donold F Mcleon BSc {Hons) CEng FIEE 6cm horizontal by 14cm vertical.

September 1998 ELECTRONICS WORLD 745 HISTORY

BBC's VERA and RCA's 19532 to support live television. experimental linear video recorders. Recently, I restored several direct In the UK, the earliest tele-record- video recordings, Fig. 1, rhat pre-dare ings come from just after the Second that period. They span the pioneering World War. In the USA, the earliest days from soon after the world's first recording appears to be of 48-line demonstration of television by John mechanical television made in 1930 Logie Baird in 1926 to rhe BBC 30- by GE of Schenectady, New York. line Television Service that ended in Ol the BBC's historic pre-war 405- 1935. They are now recognised as line service that started in 1936, bein_e the earliest video recordings in there is no recorded material other the world. than newsreel and film inserts used How could such recordings have

Fig. 4. lohn Logie Baird in 1927 at the Leeds demonstration to the BA. He is posing with a wax cylinder video record/playback system - the Fig. 3. The Baird precursor to standard called for a 'Phonovision'. vertical letter-box The drive shaft format designed for probably viewing people from connected the head-and shoulders Nipkow camera to long-shot. The disc with the subjects that came cylinder drive. across best were No cylinder Fig, 5. This frame-seguential colour those that showed recordings have lSJine dithered image from normal plenty of movement. survived. audio cassette tape was generated by The characteristic the author to simulate what Baird curved picture may have seen in his studio in 1928, comes from using a Nipkow disc.

Fig. 5. The author's modelling of Baird's Phonovision recording studio of 1927/28 shows the drive-shaft from the scanning disc connected through a 3:1 worm gear to the record platter.

746 ELECTRONICS WORLD September 1998 H!STORY

been made decades before Ampex's achievement? To answer this, we need Fig. 7. Baird's patent for the to review television's roots. 'Phonovisor'. A Nipkow disc under the record platter The dawn of television provides what must be the Spurred on by the discovery of the light cheapest and simplest video sensitivity of selenium in 1873, the replay device ever designed. transmission and reception of still pic- The Phonovisor required the tures over cable was demonstrated in specially prepared the late l9ttr century without the advan- Phonovision discs to be tage of electronics. Fleming's thermion- rccorded synchronously with ic diode valve in 1904 and de Forest's the camera disc. Looking into triode valve and amplifier of l9l2 the viewport, the picture kicked off the electronic revolution that would be seen pertecily was essential for television. By the stable, independent of early twenties, news-picture'facsimi- playback speed. les', some even using digital coding,3 spanned thousands of miles. In contrast to these slow, yet high quality transmissions, television required several pictures per second to give the perception of motion. The advantages offered by electron tubes for television camera and display were recognised (19084, l9l ls) well before their practicality. The practical electron tube display first appeared in the twenties and the camera - a major technological challenge in itself- in the thirties. Several mostly independent pioneers around the world, including Baird in the UK and Jenkins in the USA, focused on the achievement of a practical television system by adapting what already existed to their purpose. They used the only method of scanning the scene available - mechanical scanning. Of the many methods developed for scanning. the Nipkow disc6 became the Fig. 8. The experimental'Phonovisor' replay device used a large diameter Nipkow most popular. It supported the devel- disc underneath the record platter, A light source at the right shines up through opment of several of the first practical the disc via a mirror. This arrangement could also have been used for recording. television systems for almost half a century after its patent. standard of 1929-1935 was 30 lines per lnventions The Nipkow disc was normally one frame refreshing 12.5 times per second Spurred on financially and technical- spiral of holes or apertures spread Fig. 3. ly by his early demonstrations, from equally around the outer part of a flat Line scanning was vertical, from bot- 1926 to 1928 Baird patented and disc, Fig. 2. The path each aperture tom to top with frame scanning from developed a series of innovations that swept out, through the angle between right to left. Baird chose an aspect ratio Covered almost every engineering apertures, corresponded to a line in the of 3:7 - a vertical letterbox, optimised aspect of television, Fig. 4. image. The radial distance of each suc- for televising individuals from close-up . He demonstrated colour television, cessive aperture changed in equal steps portrait to long-shots. Fig. 5,.stereoscopic television, (near) so that, in one revolution, all the aper- The mechanical nature of his infrared. and long-distance transmission. tures swept out the area of one tv Nipkow-disc-based system, and the In ear,ly 1928, he demonstrated recep- frame. sensitivity and bandwidth of photo- tion of pictures across the Atlantic in By masking off the area and placing a cell-amplifiers, constrained his tele- East Coast USA from transmissions in photocell behind it, we have a televi- vision picture to mere tens of lines Surrey, England. sion camera. By placing a variable light' rather than the hundreds of lines of In the months leading up to that event, source - usually a neon - behind a the electronic systems emerging in the he not only transmitted live images, but similar disc, we have a television dis- thirties. also used his latest experiment, play. With synchronisation of camera However, this low definition turned videodisc recordings.T These and other with display, we have the vision chan- out to offer a distinct advantage. The demonstrations served to establish Baird nel for television. highest vision frequency was so low in the public's eye and to raise general that it was in the audio spectrum. Both awareness of a television revolution. The first demonstration this narrow bandwidth and the ease of Today, littte evidence remains of of television creating different scanning arrange- these early achievements. This makes it First with a demonstration of scanning ments were the main reasons why dilficult to be factual about Baird's con- and display of moving pictures in Baird was able to achieve so many tribution to television - especially in his reflected light was John Logie Baird on 'firsts' - years before they were repeat- most publicised creative era of the late 26th January 1926. Baird's transmitted ed in electronic television. 1920s.

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Various interpretations of his works discoveries made. Studying rhe derails have both over- and under-stated of the video signal tells us the camera Baird's importance. However, the sig- type and even how well it was built. In nificance of one of his achievements addition, analysing the faults on the from that period has only recently been recordings gives a unique and in-depth recognised. This is his recording of understanding of the difficulties Baird television - the first in the world. encountered. l4 From previously being mere curiosities, the discs have today Phonovision and the become one of Baird's most historical 'Phonovisor' legacies. ln 1926, Baird applied for a patent on an idea for recording vision and sound The 30-!ine broadcasts signals.E He called this process In September 1929, after much lobby- 'Phonovision'. ing, the Baird Television Development What made Phonovision unique was Company started a series of experi- its mechanical coupling of the camera mental transmissions through the BBC mechanism to the record platter, Fig. 6. transmitters. The same linkage on playback would For nearly three years, for no fewer have ensured a rock-steady picture than five times a week, the Baird from the disc. In one simple concept, Company produced its own pro- Baird eliminated the effect of speed grammes from its laboratories in Long variation during recording and play- Acre. In August 1932, the BBC took Fig. 9. On the left is an attempt from the seventies at replaying back. over full control and started the BBC a Phonovision (lOth disc lanuary t92B) without using a A subsequent patentg described the Television Service with regular pro- computen On the right is the same disc and subject enhanced 'Phonovisor', Fig. 7. This was to be a gramming from studio 'BB' in the by custom software signal and image processing. simple machine used for both playing basement of Broadcasting House. back and displaying pictures from the It now seems that a few of the enthu- Phonovision discs. The Phonovisor siasts watching the television pro- Fig. 10, Baird's temp would have looked like a conventional grammes on their Baird 'Televisors' secretary, Mabel gramophone. However, mounted coax- were moved to use their domestic Pounsford, captured on ially with the disc platter was a hori- audio recorders to record the vision disc on 28 March 1928. zontal Nipkow disc with the apertures signal for subsequent playback. Her identity was on the rim outside the disc platter. Although the quality of the result discovered after the Although highly innovative in its would have seriously disappointed restored pictures were simplicity and inherently cheap, neither them, they very fortunately kept the broadcast in 1993 on Phonovision discs nor the Phonovisor discs safe rather than destroying them. Channel 4 and recognised ever appeared commercially. Unlike by a relative. Baird's other experiments, the repro- Off-air recordings duction of pictures from the News of my discoveries from the Fig. 1t . The Phonovision discs - though undoubt- Phonovision discs triggered some earliest-known edly attempted in the laboratory, Fig. 8 tremendous finds. A single privately video recording of - was never publicly demonstrated. recorded aluminium disc found in broadcast From his own comments, it would 1996, with just the cryptic words television from the seem that Baird was never sufficiently "Television 1933" written in ink on the BBC,2l April satisfied with the picture quality to label, was the first. 1933. The main give such a demonstration. The material on the disc overturns feature, captured Baird moved on to other ideas and established views on the 30-line BBC on disc, was the abandoned Phonovision. He passed a programmes. After restoration and Paramount Astoria few of the discs to museumslo and to analysis, this disc contains the earliest Girls with their his friends and employees. Over sub- known recording of a television broad- high-kicking sequent years, many people attempted cast in fact, a television special Fig. routine. - reproduction of images from the 1 1. It was broadcast in April 1933, just Phonovision discs.ll Their efforts eight months after the start of the BBC yielded only crude distorted images, 30-line Television Seriice. Fig. 9. The camera technique, lighting tech- What Baird could not have realised nique and production features are all is that more than sixty years later the unusual and unique. The rapid pace of faults during recording could be cor- the performance is stunning and pro- rected in a personal computer,l2'I3 vides us today with a true measure of restoring the latent image on his discs Britain's heritage of television pro- to a recognisable form. Those images gramme making. give a remarkable insight into those In early 1998, another discovery was pioneering days of television, Fig. 1 0. made. A set of unmarked privately But the images are only part of the recorded aluminium discs has turned

748 ELECTRONICS WORLD September 1998 HISTORY

Fig. 12. Far left Believed to be from a BBC out to contain the highest quality origi- broadcast in nal 30-line vision recordings known to 1934-35, this is exist. Eetty Bolton, Het From the video characteristics, they performance is were extracts from BBC transmissions stunning and from the latter part of the 30-line ser- easily makes her vice. By that time. the BBC had moved the'Madonna'of out of Broadcasting House into a new thirties videos. studio in l6 Portland Place. One of the singers on the discs is Betty Bolton, Fig. 12. Betty is a well- known contralto, who perfbrmed over a dozen times in front of the 30-line cam- bras. Her visual perfbrmance on disc is exceptional - even on a sixty-year old Fig. 1 3. ln early corroded aluminium disc she still man- 1935, a test disc aged to charm her re-discoverer. of still images was In 1935, the flrst video disc was sold sold for'lining up' in the UK. A 78 revlmin test disc 30Jine displays. A intended fbr 'lining up' displays, it con- few months later, tains only static lantem slides of cartoon the 30-line service figures, Fig. 13. Although a collector's was terminated, item today, this, the 'Major rendering Radiovision' disc, contains little of thousands of interest for the historian. It is certainly receivers, and this not. as has been claimed, 'Phonovision'. test disc, obsolete, The parallel developments of television in other countries suggest that there should be similar discs around the world. To date, I have only fbund discs of British television. It may be simply that, like the British discs before this restoration work, recordings made in other countries were written off as unplayable. See more... The author's website at http ://www.dfm.d i rcon.co.u k ln summary Acknowledgements contains sound and video clips from all the restored The discovery and restoration of the My thanks go to all those who have discs. Bear in mind that the images shown here have discs falls somewhere between being a supported and encouraged this private been restored from poor quality, distorted audio computer-age detective story and a research throughout the years. Special recordings, so they do not represent the quality of the practical example of technological thanks go to Ray Herbert, Eliot Levin original 30-l ine broadcasts. archaeology. of Symposium Records, Nicholas Moss Applying the latest technological of the BBC and the owners of the discs advances ofthe eighties and nineties has fbr their tieely-given help and support 8. Baird, J L, British Patent No 289104, given us a unique view of the latest fbr the recent discoveries. r applied fbr l5 October 1926. technological developments of the 9. Baird, J L, British Patent No 324049, twenties and thirties. What makes this References applied for l0 October 1928. so fascinating is that the material comes l. Ginsburg, C P, 'The Birth of Videotape 10. Science Museum Inv. 1935-33-5. from such a dynamic and important Recording', 82nd Conv SMPTE. 'Phonovision Record, 1928. Lent by period in Britain's technological history. October5.1957. Baird Television, Ltd.' (author's After 1500 programmes, the BBC 30- 2. Olson, H F et ul.'A System for remarks: this is RWT620-6). line service closed on I I September Recording and Reproducing Television I l. Voore, T, BBC, Private 1935. In November 1936, the BBC re- Signals', RCA Review, March 1954, Communication. 1984. opened its television service with high- XV pp.3-l?. 12. Mclean, D F, 'Using a Micro to definition television. The massive tech- 3. Jenkins, C F, Vision by Radio, 1925, process 30-line Baird television nology leap that television had made National Capilal Press Inc. recordings', Electronics und Wireless left recording technology far behind. It .1. 'Distant Electric Vision', Letter by A World. October 1983. would- be nearly .twenty years betbre A Campbell Swinton, l2 June 1908, 13. Mclean, D F, 'The Recovery of direct video recording could catch up. Nature. Phonovision'. tEE Third Intl Conf on I plan to produce two fbllow-up arti- 5. Address to the Roentgen Society, A A Image Processing & Its Applications, cles covering in more detail the dis- Campbell Swinton, T November l9l l. 1989, pp. 300-304.0 coveries fiom Baird's Phonovision and Nipkow. P. DRP Patent 30105, Jan 14. Mclean, D F, 'Computer-based the restoration techniques used, the later I 884. Analysis & Restoration of Baird 30- BBC tansmissions and how they appear Clapp, B. Personal collection (R M line TV Recordings', Jounrul of the in conlext with today's television. Herbcrt). Rolul Televisiur Socir,lr'. April 1985.

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