# How Television Was Invented > On 2 November 1936 the BBC opened its television service at Alexandra Palace in London, with two rival systems taking turns. This film explains the problem they solved, sending a whole picture down one wire, and how it was cracked: selenium that turns light into current, Nipkow's spinning disc, Baird's 30-line televisor of 1926, Braun's cathode-ray tube, Campbell-Swinton's plan, Farnsworth's image dissector and the storage camera tubes, how a raster, interlacing and sync pulses build a picture, the contest of 1936, colour with the shadow mask, and how television came to Thailand in 1955. Interactive film: https://www.planetpast.com/stories/how-television-was-invented/ Publisher: PlanetPast (https://www.planetpast.com/) · d => T('readPublished', l, { d: dateIn(d, l) }) 2026-11-02 · History, Technology, Physics ## Prologue ### A picture, one line at a time *History · Technology* Ninety years of the BBC’s television service, and the idea that made it work. At three o'clock in the afternoon on the second of November 1936, the BBC opened its television service from Alexandra Palace, in north London. On that first day, two rival machines took turns to make the pictures, and a coin toss decided which one went first. Both were answers to the same puzzle. How do you send a moving picture down a single wire? Ninety years later, here is how that puzzle was solved. > This is direct television from the studios at Alexandra Palace. (Presenter Leslie Mitchell, opening the broadcast, 1936 (as quoted by PA)) ![The service closed again when war came in 1939, and did not return until June 1946. AI-generated still.](https://assets.planetpast.com/a/38/3813de59c370c1db.jpg) - **2**: rival systems, one studio each - **heads or tails**: who goes first: the answer comes in chapter V - A picture: light everywhere at once - A wire: one signal at a time - Television: make the second carry the first - **19 Sep – 19 Nov 2026**: anniversary season of talks and screenings Prologue #### Ninety years of BBC television Wikipedia, BBC Television: the BBC Television Service officially launched at 3 pm on 2 November 1936 from a converted wing of Alexandra Palace in London. National Science and Media Museum: the opening ceremony was broadcast twice, first from the Baird studio and then from the Marconi-EMI studio, after Baird won a coin toss. The Irish News / PA (20 August 2026): the Alexandra Park and Palace Charitable Trust is holding “BBC TV 90 at Ally Pally”, a season of talks, screenings and events from 19 September to 19 November 2026; presenter Leslie Mitchell opened the 1936 broadcast with “This is direct television from the studios at Alexandra Palace.” The anniversary is the hook. The rest of the film is the well-documented history and the working principle of television. The 3D scenes are simplified teaching models, not to scale, and much slower than the real thing. Sources: [Wikipedia: BBC Television (launch, the two systems, 1939 shutdown, 1946 return, set numbers)](https://en.wikipedia.org/wiki/BBC_Television); [National Science and Media Museum blog: 80 years ago, the opening of the British television service](https://blog.scienceandmediamuseum.org.uk/80-years-ago-the-opening-of-the-british-television-service/); [The Irish News / PA (20 Aug 2026): New Alexandra Palace programme to mark 90 years since first BBC TV broadcast](https://www.irishnews.com/entertainment/new-alexandra-palace-programme-to-mark-90-years-since-first-bbc-tv-broadcast-YOJVCIXFDVJRNGQVBY62RYZ2TA/) ## Chapter I · Light into current ### A picture is a whole field of light at once. A wire, or a radio wave, carries only one changing signal at a time. So break the picture into points, and send the brightness of each point one after another, very fast. Watch the signal on the wire rise for bright points and fall for dark ones. For that, you need something that turns light into a current. In 1873, the English engineer Willoughby Smith found that the electrical resistance of selenium changes sharply with the light falling on it. Put it in a circuit with a battery: in bright light more current flows, in the dark less. - A picture: millions of points at once - A wire: one value at each instant - The fix: send the points in turn - **24 × 18**: points: a very coarse picture - **432**: brightness values sent in a row ![A grey, metallic-looking element: in light it conducts better than in the dark. AI-generated still.](https://assets.planetpast.com/a/84/845797277e21d59f.jpg) - **light**: lower resistance: more current - **dark**: higher resistance: less current Chapter I · Light into current #### One wire, one signal History of Information: in 1873 the English electrical engineer Willoughby Smith discovered that the electrical resistance of selenium changes sharply depending on how much light falls on it, the effect called photoconductivity; it gave a way to turn images into electrical signals and a basis for television. University of St Andrews: television uses raster scanning to turn a picture into a single serial stream, reading the brightness along a set path line by line. Try it: scan slowly to follow the point, then fast. The picture is an illustration drawn for this film. The 3D scenes are simplified teaching models, not to scale, and much slower than the real thing. Sources: [History of Information: Willoughby Smith discovers the photoconductivity of selenium (1873)](https://www.historyofinformation.com/detail.php?id=1090); [University of St Andrews, Scots Guide to electronics: TV scanning, frames and interlacing](https://www.st-andrews.ac.uk/~www%5Fpa/Scots%5FGuide/RadCom/part21/page2.html) ### In 1885 the German engineer Paul Nipkow patented a way to do the breaking up with a machine: a spinning disc with a spiral of holes. Each hole crosses the picture a little lower than the one before, so one turn of the disc sweeps the whole scene, one line per hole. The light through each hole falls on a light-sensitive cell, which turns it into a current that rises and falls. At the receiver, a lamp flickers with that current behind a second disc spinning in step. Spin fast enough, and the eye sees one picture. ![Lit from behind: the holes step inward as they go round. AI-generated still.](https://assets.planetpast.com/a/93/9309aa940818771f.jpg) - 1 hole = 1 line - e.g. 30 holes = 30 lines - 1 turn = 1 complete picture - **bright**: more current - **dark**: less current - Same number of holes - Same speed, same moment - A lamp instead of a light cell Chapter I · Light into current #### Nipkow’s disc IEEE Spectrum: the German engineer Paul Nipkow patented an “electric telescope” in 1885. His disc had perforations offset in a spiral, so each hole captured one scan line in turn and each line became an electrical signal. In Baird’s version, lenses focused reflected light onto a photoelectric cell; in the receiver, the amplified signal drove a neon lamp behind a second disc spinning at the same speed, and the image appeared complete through persistence of vision. Try it: slow, the disc paints one line at a time; fast, the lines blend. Real discs turned many times a second. The 3D scenes are simplified teaching models, not to scale, and much slower than the real thing. Sources: [IEEE Spectrum: The first television (Nipkow, Baird’s televisor, Farnsworth, the iconoscope)](https://spectrum.ieee.org/first-tv) ## Chapter II · The spinning disc ### On the twenty-sixth of January 1926, the Scottish inventor John Logie Baird showed his televisor to members of the Royal Institution, at his workshop in Soho, London. His discs had thirty holes, so his pictures had thirty lines. The face shown that day was a ventriloquist's dummy, because the lamps were too hot and too bright for a person. A person was shown as well. The image was small and dim and it flickered, but it moved. Try more lines and see what each one adds. - **30**: holes in each disc - **2**: discs: one to send, one to receive ![The picture showed through a small window, lit by a neon lamp. AI-generated still.](https://assets.planetpast.com/a/e6/e6042a40d7e519b3.jpg) - Baird, 1926: 30 - Baird system, 1936: 240 - Marconi-EMI, 1936: 405 Chapter II · The spinning disc #### The televisor, 1926 IEEE Spectrum: on 26 January 1926 Baird demonstrated his televisor to members of the Royal Institution at his laboratory in Soho, London; the image was the face of a ventriloquist’s dummy, and a human subject was also shown. His system used two discs, each with 30 holes, one in the transmitter and one in the receiver spinning at the same speed. Early tests used dummies because the lights were too hot and bright for people. An IEEE Milestone marks the 1926 demonstration. Try it: 30, 60 and 120 lines on the same picture. The face is an illustration, not the dummy Baird used. The 3D scenes are simplified teaching models, not to scale, and much slower than the real thing. Sources: [IEEE Spectrum: The first television (Nipkow, Baird’s televisor, Farnsworth, the iconoscope)](https://spectrum.ieee.org/first-tv) ### Baird kept improving. In 1928 he sent television across the Atlantic, from London to Hartsdale, New York, and showed a mechanical colour system. But a disc has limits. Watch it grow to a hundred and twenty holes: more lines mean more and smaller holes, on a disc that must spin fast and true, and less light gets through each one. - 1925: Silhouettes shown at Selfridges, London - 1926: Royal Institution demonstration - 1928: Across the Atlantic; mechanical colour - 1929: BBC experimental broadcasts - 1931: The Derby, live - **1929–1937**: years the BBC used it - **30 → 240**: lines, as it was upgraded - More lines: more holes - Smaller holes: less light - A heavy disc must spin in perfect step ![Baird's discs reached 240 lines by 1936; the all-electronic rival at the same station ran 405. AI-generated still.](https://assets.planetpast.com/a/06/066c90825369c0c2.jpg) - **30 → 120**: holes - **¼**: the height of each line, and of each hole Chapter II · The spinning disc #### How far a disc could go IEEE Spectrum: Baird’s first demonstration, in March 1925 at Selfridges in London, showed shadowy silhouettes. In 1928 he made the first transatlantic television transmission, from London to Hartsdale, New York, and demonstrated a mechanical colour system. The BBC ran experimental broadcasts of his system from 1929 and used it from 1929 to 1937, upgrading from 30 to 240 lines. In 1931 he made the first live broadcast of the Epsom Derby. Why discs struggled with more lines is explained here from the geometry of the disc; the 240-line Baird system of 1936 in fact filmed the scene and then scanned the film (chapter V). The 3D scenes are simplified teaching models, not to scale, and much slower than the real thing. Sources: [IEEE Spectrum: The first television (Nipkow, Baird’s televisor, Farnsworth, the iconoscope)](https://spectrum.ieee.org/first-tv) ## Chapter III · Beams of electrons ### The way past the disc had been found years earlier, in physics laboratories. In 1897, the German physicist Karl Ferdinand Braun built a cathode-ray tube: a glass tube in which a beam of electrons, then called cathode rays, is focused into a spot that makes a fluorescent screen glow. A magnet outside the tube could steer that spot, and trace patterns with it. Electrons weigh almost nothing, so a beam can be swung across a screen far faster than any disc can turn. ![Where the beam lands, the coated glass glows green. AI-generated still.](https://assets.planetpast.com/a/30/308d00b0cfb053bf.jpg) - A gun shoots electrons - Coils or plates steer the beam - A coated screen glows where it lands - **a disc**: heavy: must be spun up and held in step - **a beam**: nearly weightless: steered by a field - **1897**: the focused cathode-ray tube - **1909**: Nobel Prize in Physics, shared with Marconi Chapter III · Beams of electrons #### Braun’s tube Engineering and Technology History Wiki: in 1897 Karl Braun showed that a cathode ray could be focused to a point that makes a fluorescent screen glow, and used an external magnet to trace patterns on it; the tube laid the groundwork for later devices such as the television picture tube and radar tubes. He shared the 1909 Nobel Prize in Physics with Guglielmo Marconi for their work on radio. That the beam can sweep far faster than a disc follows from the electron’s tiny mass; it is the film’s explanation, not a quoted figure. The 3D scenes are simplified teaching models, not to scale, and much slower than the real thing. Sources: [Engineering and Technology History Wiki: Karl Braun](https://ethw.org/Karl_Braun) ### In 1908, the British engineer Alan Archibald Campbell-Swinton wrote to the journal Nature with a plan: use two beams of electrons, one at the camera and one at the receiver, swept in step by electromagnets. In a lecture in London in 1911 he described the whole system. It was a design on paper: the technology to build it did not yet exist. It would be almost thirty years before a service built on beams like these went on the air. > …the employment of two beams of cathode rays (one at the transmitting and one at the receiving station)… (A. A. Campbell-Swinton, “Distant Electric Vision”, Nature, 18 June 1908) ![Campbell-Swinton never built his machine: he judged the experiment too costly for the chance it would work. AI-generated still.](https://assets.planetpast.com/a/1c/1cc1459b7405ff7b.jpg) - Cathode-ray tubes at both ends - Camera screen: a mosaic of tiny rubidium cubes - Nothing that spins - 1908: Letter to Nature - 1911: Lecture with the full design - 1936: Electronic service on air in London Chapter III · Beams of electrons #### Distant electric vision Wikipedia, Alan Archibald Campbell-Swinton: his letter “Distant Electric Vision” appeared in Nature on 18 June 1908, answering an article by Shelford Bidwell. He proposed two beams of cathode rays, one at the transmitting and one at the receiving station, deflected synchronously by electromagnets, with the receiving beam striking a fluorescent screen. In a 1911 speech in London he described in detail how it could be done, with cathode-ray tubes at both ends and a transmitting screen made as a mosaic of isolated rubidium cubes. The 3D scenes are simplified teaching models, not to scale, and much slower than the real thing. Sources: [Wikipedia: Alan Archibald Campbell-Swinton (the 1908 letter to Nature)](https://en.wikipedia.org/wiki/Alan_Archibald_Campbell-Swinton) ### In San Francisco, the young American inventor Philo Farnsworth built a camera with no moving parts. On the seventh of September 1927, his image dissector sent its first picture: a single straight line. It turned the picture into a cloud of electrons and swept the cloud past a tiny opening, reading one point at a time. But each point was seen only for an instant, so the scene needed very bright light. At RCA, a team under Vladimir Zworykin had a working iconoscope by 1931. Tubes like it kept collecting charge from the light between scans, like a bucket left out in the rain rather than a cup held out for a moment, so they were far more sensitive. In Britain, EMI built its own electronic camera, the Emitron. - Jan 1927: Patent application filed - 7 Sep 1927: First image: a straight line - Sep 1928: Shown to the press - 1930: US patent 1,773,980 issued ![Light falls on a flat sensitive plate inside the glass. AI-generated still.](https://assets.planetpast.com/a/e6/e6289004c0247ab2.jpg) - Dissector: reads each point only as the opening passes - Storage tube: each point gathers charge the whole time - Result: storage tubes need far less light - **1931**: RCA: a working iconoscope - **1936**: EMI: Emitron cameras on air in London Chapter III · Beams of electrons #### Cameras with no moving parts Wikipedia, Image dissector: a lens focuses the image onto a photosensitive layer that emits electrons in proportion to the light; magnetic fields or plates sweep this electron image across a small aperture, so only electrons from a tiny area reach the detector at a time. It does not store charge, so each point is seen only briefly, which was its main limitation; charge-storage tubes such as the iconoscope accumulated charge over time, were far more sensitive and replaced it during the 1930s. Farnsworth filed his patent application on 7 January 1927; the device transmitted its first image, a simple straight line, on 7 September 1927 at his San Francisco laboratory; he showed it to the press on 3 September 1928, and US patent 1,773,980 was issued on 26 April 1930. IEEE Spectrum: Zworykin applied for an iconoscope patent in 1923, and his team at RCA had a working iconoscope in 1931; both tubes still needed very bright lights. National Science and Media Museum: the Marconi-EMI system used Emitron cameras. Who “invented television” is argued over to this day: Baird, Farnsworth, Zworykin and others each made a different piece of it. This film names what each did, with dates. The 3D scenes are simplified teaching models, not to scale, and much slower than the real thing. Sources: [Wikipedia: Image dissector](https://en.wikipedia.org/wiki/Image_dissector); [IEEE Spectrum: The first television (Nipkow, Baird’s televisor, Farnsworth, the iconoscope)](https://spectrum.ieee.org/first-tv); [National Science and Media Museum blog: 80 years ago, the opening of the British television service](https://blog.scienceandmediamuseum.org.uk/80-years-ago-the-opening-of-the-british-television-service/) ## Chapter IV · Drawing a picture ### This is how the 1936 electronic pictures were drawn, and every picture-tube set after them. The beam starts at the top left, sweeps across one line, snaps back, and sweeps the next line, a little lower. The picture signal turns the beam up for bright points and down for dark ones. This pattern of lines is called a raster. Britain's electronic system of 1936 used four hundred and five lines. Britain's later standard used six hundred and twenty-five, with twenty-five complete pictures every second. To cut flicker, each picture is sent in two halves, called fields: first the odd lines, then the even lines, each in a fiftieth of a second. So every part of the screen is lit fifty times a second, not twenty-five. This is interlacing. Compare the two. - Trace: left to right - Retrace: snap back, beam blanked - Down a step, and again ![Close to the glass, a picture is only rows of glowing light. AI-generated still.](https://assets.planetpast.com/a/b6/b676c1b5dbb89a76.jpg) - **405**: lines, Britain 1936 - **625**: lines, Britain’s later standard - **25**: complete pictures a second - **50**: times a second each area is lit - Field 1: lines 1, 3, 5 … - Field 2: lines 2, 4, 6 … - Each field: 1/50 of a second Chapter IV · Drawing a picture #### The raster Video History Project: the beam sweeps across and slightly down the screen; each left-to-right sweep is a trace, followed by a retrace hidden by a blanking pulse; the 525-line US system splits each frame into two fields of odd and even lines, 60 fields or 30 frames a second. University of St Andrews: the UK system uses 625 lines and 25 frames a second, each sent as two half-frames, odd lines then even lines, each in 1/50 second, so every part of the screen is refreshed 50 times a second and flicker is reduced. National Science and Media Museum: the Marconi-EMI system of 1936 scanned 405 lines, interlaced, left to right and top to bottom; it stayed the British standard until the 625-line UHF standard of the 1960s. Try it: interlaced or progressive, and slower. The tube draws far fewer lines than a real set, enormously slowed. The 3D scenes are simplified teaching models, not to scale, and much slower than the real thing. Sources: [Video History Project: How a monitor and camera work, the scanning process](https://www.videohistoryproject.org/node/7051); [University of St Andrews, Scots Guide to electronics: TV scanning, frames and interlacing](https://www.st-andrews.ac.uk/~www%5Fpa/Scots%5FGuide/RadCom/part21/page2.html); [National Science and Media Museum blog: 80 years ago, the opening of the British television service](https://blog.scienceandmediamuseum.org.uk/80-years-ago-the-opening-of-the-british-television-service/) ### The camera and the set must scan in perfect step. So the signal carries timing pulses: one to start each line, and another to start each field. Lose the line pulse, and the picture tears into diagonal stripes. Lose the field pulse, and it rolls up or down the screen. Try both. Your eyes do the rest. Persistence of vision, and the afterglow of the screen, blend the flying lines into one moving picture. - Horizontal sync: start a line - Vertical sync: start a field - Blanking: hide the beam on its way back - **tearing**: line sync lost: diagonal lines - **rolling**: field sync lost: picture drifts up or down - **eye**: persistence of vision - **screen**: the phosphor keeps glowing briefly ![The timing pulses sit in a part of the signal blacker than black, so they never appear on the screen. AI-generated still.](https://assets.planetpast.com/a/66/66bbd33c4ece546b.jpg) Chapter IV · Drawing a picture #### Keeping in step Video History Project: sync pulses keep the camera and the monitor scanning at the same rate and in step. A horizontal sync pulse starts each trace; losing it causes diagonal lines. A vertical sync pulse starts each field; losing it causes rolling. Without sync the image is not readable. Because of persistence of vision, viewers see continuous motion. University of St Andrews: persistence of vision and the phosphor’s afterglow help smooth the picture. Try it: lose the line pulse, then the field pulse. The faults are drawn as schematics. The 3D scenes are simplified teaching models, not to scale, and much slower than the real thing. Sources: [Video History Project: How a monitor and camera work, the scanning process](https://www.videohistoryproject.org/node/7051); [University of St Andrews, Scots Guide to electronics: TV scanning, frames and interlacing](https://www.st-andrews.ac.uk/~www%5Fpa/Scots%5FGuide/RadCom/part21/page2.html) ## Chapter V · The contest of 1936 ### Back to Alexandra Palace, where Baird had won the toss and gone first. In Studio A, Marconi-EMI's fully electronic system scanned four hundred and five interlaced lines with Emitron cameras. In Studio B, Baird's company used two hundred and forty lines and a cumbersome trick. It filmed the scene, developed the film in tanks within moments, and then scanned the film. The BBC ran the two on alternate weeks. After closedown on the thirtieth of January 1937, it dropped Baird's system for good. ![Boxy cameras on wheeled stands and banks of hot lights. AI-generated still.](https://assets.planetpast.com/a/d5/d5a5a2f2790b490c.jpg) ![The gallery sees every camera at once, and the director cuts between them live, with no way to go back. AI-generated still.](https://assets.planetpast.com/a/3c/3c702b6ead7a8660.jpg) - **405**: Marconi-EMI: electronic, interlaced - **240**: Baird: film first, then scanned - 2 Nov 1936: Service opens; systems alternate - 30 Jan 1937: Last Baird transmission - After: 405 lines only Chapter V · The contest of 1936 #### The contest National Science and Media Museum: Studio A used the fully electronic Marconi-EMI system with Emitron cameras, scanning 405 lines, interlaced; Studio B used Baird Television’s 240-line sequential system with an intermediate film process, in which a 35 mm camera shot the scene above tanks for near-instant developing, fixing and scanning. The film system was considered too cumbersome and was dropped after a few months. Wikipedia, BBC Television: the two ran on alternate weeks on a six-month trial; early sets could receive both; the Baird system was dropped after closedown at 22:00 on Saturday 30 January 1937, judged too cumbersome and visually inferior. Try it: switch between a Baird week and an EMI week. The two screens exaggerate the line structure to make the difference visible. The 3D scenes are simplified teaching models, not to scale, and much slower than the real thing. Sources: [National Science and Media Museum blog: 80 years ago, the opening of the British television service](https://blog.scienceandmediamuseum.org.uk/80-years-ago-the-opening-of-the-british-television-service/); [Wikipedia: BBC Television (launch, the two systems, 1939 shutdown, 1946 return, set numbers)](https://en.wikipedia.org/wiki/BBC_Television) ### Television was a luxury. British manufacturers made about nineteen thousand sets before production stopped in 1939. On the first of September 1939, the service went off the air. Officials feared the transmitter could guide enemy aircraft to London, and its engineers were needed for war work, including radar. It came back on the seventh of June 1946. - **18,999**: sets made, 1936 to September 1939 - **25,000–40,000**: homes the service was estimated to reach ![Some early sets pointed the tube upward and showed the picture in a mirror in the lid. AI-generated still.](https://assets.planetpast.com/a/99/99b6450031222df2.jpg) ![A set cost about as much as a small car, and in 1936 only a few hundred homes within range had one. AI-generated still.](https://assets.planetpast.com/a/7d/7d866b070aea2b08.jpg) - 1 Sep 1939: Service suspended - 7 Jun 1946: Service returns Chapter V · The contest of 1936 #### Silence, then a return Wikipedia, BBC Television: Britain’s Radio Manufacturers Association counted 18,999 television sets manufactured from 1936 until production stopped in September 1939; the service was estimated to reach 25,000–40,000 homes before the war. It went off the air on 1 September 1939, because officials feared the VHF transmissions could guide enemy aircraft towards London and because many technical staff were needed for the war effort, including radar. BBC Television returned on 7 June 1946. The 3D scenes are simplified teaching models, not to scale, and much slower than the real thing. Sources: [Wikipedia: BBC Television (launch, the two systems, 1939 shutdown, 1946 return, set numbers)](https://en.wikipedia.org/wiki/BBC_Television) ## Chapter VI · Colour, and Thailand ### Colour needs three pictures at once, in red, green and blue. The shadow-mask tube put three electron guns in the neck of one tube. Just behind the screen sits a metal mask full of tiny holes. The three beams arrive at slightly different angles, so through each hole, each beam lands only on a dot of its own colour. The dots sit in groups of three, called triads. Switch the guns on and off. RCA produced its first tubes of this kind in 1950. The American NTSC colour standard, which rests on that system, was worked out between 1950 and 1953. ![Three guns in the neck; a thin perforated mask just behind the glass. AI-generated still.](https://assets.planetpast.com/a/45/45f62658a1f47170.jpg) - Red + green = yellow - Green + blue = cyan - All three = white - **3**: phosphor dots: red, green, blue - **1**: hole in the mask in front of them - 1938: German inventor Werner Flechsig patents the basic idea - 1950: First RCA tubes produced - 1950–53: NTSC colour standard refined - mid-1950s: Colour sets on sale in the US Chapter VI · Colour, and Thailand #### Three beams, one mask Wikipedia, Shadow mask: a metal plate with tiny holes sits just behind the front glass; three electron guns at the back fire beams that approach the mask from slightly different angles, so each beam lands only on phosphor dots of its own colour, arranged in red, green and blue triads. The German inventor Werner Flechsig patented the basic concept in 1938; RCA made it practical, producing its first tubes in 1950; the NTSC colour standard, which RCA’s system underpinned, was refined through studies from 1950 to 1953, and sets were on sale by the mid-1950s. Try it: switch the red, green and blue guns. The colour names are those of mixed light, not paint. The 3D scenes are simplified teaching models, not to scale, and much slower than the real thing. Sources: [Wikipedia: Shadow mask](https://en.wikipedia.org/wiki/Shadow_mask); [IEEE Spectrum: The first television (Nipkow, Baird’s televisor, Farnsworth, the iconoscope)](https://spectrum.ieee.org/first-tv) ### In Thailand, television arrived on the twenty-fourth of June 1955, using the American NTSC standard. About a thousand sets had arrived in Bangkok from RCA that April, selling for six to eight thousand baht each. Colour broadcasts began in 1967, using the European PAL system with six hundred and twenty-five lines. Digital television started in 2014, and the old analogue signal was switched off by 2020. ![A crowd gathered at a shop window to watch. AI-generated still.](https://assets.planetpast.com/a/26/261606e2211e64fe.jpg) - **~1,000**: sets from RCA - **6,000–8,000 baht**: price of one set - 1955: First broadcasts, NTSC - 1967: Colour begins, PAL 625 lines - 1975: Full-time colour - 2014: Digital terrestrial TV launches - 2020: Analogue switch-off completed - **NTSC**: American: 525 lines, 30 pictures a second - **PAL**: European: 625 lines, 25 pictures a second Chapter VI · Colour, and Thailand #### Television comes to Thailand Wikipedia, Television in Thailand: television was first officially introduced on 24 June 1955, in NTSC; colour telecasts (PAL, 625 lines) began in 1967 and full-time colour in 1975; digital terrestrial services launched in April 2014 and the analogue switch-off was completed in 2020. Bangkok Post, Thailand Journey: about 1,000 sets arrived in Bangkok from the Radio Corporation of America in April 1955, selling for roughly 6,000 to 8,000 baht each. The screen in the 3D set shows the illustrated test picture, not a real broadcast. The 3D scenes are simplified teaching models, not to scale, and much slower than the real thing. Sources: [Wikipedia: Television in Thailand](https://en.wikipedia.org/wiki/Television_in_Thailand); [Bangkok Post, Thailand Journey: 24 June 1955, first TV channel airs; first 1,000 television sets arrive from the US](https://thailandjourney.bangkokpost.com/timeline/1955/first-tv-channel-airs-first-1000-television-sets-arrive-from-the-us) ## Epilogue ### Ninety years on, the discs and the glowing tubes are gone. Who invented television is still argued over: Baird, Farnsworth, Zworykin and others each built a different piece. And at its root, the idea they shared has not changed: turn a picture into a stream of signals, send it fast, and rebuild it in step at the other end. - 1873: Selenium reacts to light - 1885: Nipkow’s disc patented - 1897: Braun’s cathode-ray tube - 1926: Baird’s 30-line televisor - 1927: Farnsworth’s first electronic image - 1936: BBC service opens - 1955: Television in Thailand - 2020: Thai analogue switch-off ![Britain switched off its last analogue television transmitters in 2012. AI-generated still.](https://assets.planetpast.com/a/2d/2d042b10a7132f6c.jpg) - Scan: picture to a stream - Send: one signal, fast - Rebuild: in step with the sender Epilogue · Sources #### Sources Every fact in this film comes from the sources below. The chapter stills and pictures are AI-generated and show no real people, programmes or brands. The palace, discs, tubes, screens and colour mask in the 3D scenes are simplified teaching models, far slower than the real machines, and the face on the screens is an illustration drawn for this film. Who “invented television” is disputed; the film says what each inventor did and when, according to the sources. Sources: [Wikipedia: BBC Television (launch, the two systems, 1939 shutdown, 1946 return, set numbers)](https://en.wikipedia.org/wiki/BBC_Television); [National Science and Media Museum blog: 80 years ago, the opening of the British television service](https://blog.scienceandmediamuseum.org.uk/80-years-ago-the-opening-of-the-british-television-service/); [The Irish News / PA (20 Aug 2026): New Alexandra Palace programme to mark 90 years since first BBC TV broadcast](https://www.irishnews.com/entertainment/new-alexandra-palace-programme-to-mark-90-years-since-first-bbc-tv-broadcast-YOJVCIXFDVJRNGQVBY62RYZ2TA/); [IEEE Spectrum: The first television (Nipkow, Baird’s televisor, Farnsworth, the iconoscope)](https://spectrum.ieee.org/first-tv); [History of Information: Willoughby Smith discovers the photoconductivity of selenium (1873)](https://www.historyofinformation.com/detail.php?id=1090); [Engineering and Technology History Wiki: Karl Braun](https://ethw.org/Karl_Braun); [Wikipedia: Alan Archibald Campbell-Swinton (the 1908 letter to Nature)](https://en.wikipedia.org/wiki/Alan_Archibald_Campbell-Swinton); [Wikipedia: Image dissector](https://en.wikipedia.org/wiki/Image_dissector); [University of St Andrews, Scots Guide to electronics: TV scanning, frames and interlacing](https://www.st-andrews.ac.uk/~www%5Fpa/Scots%5FGuide/RadCom/part21/page2.html); [Video History Project: How a monitor and camera work, the scanning process](https://www.videohistoryproject.org/node/7051); [Wikipedia: Shadow mask](https://en.wikipedia.org/wiki/Shadow_mask); [Wikipedia: Television in Thailand](https://en.wikipedia.org/wiki/Television_in_Thailand); [Bangkok Post, Thailand Journey: 24 June 1955, first TV channel airs; first 1,000 television sets arrive from the US](https://thailandjourney.bangkokpost.com/timeline/1955/first-tv-channel-airs-first-1000-television-sets-arrive-from-the-us)