Advertising image of an HMV model 1803 television, as sold in 1950
Television has not always been the same shape. In the days of John Logie Baird's first experiments, the picture was about the size and shape of a postcard, in portrait format, with thirty lines scanned vertically to create a neon-illuminated image. Then when the BBC's 'high-definition' service was introduced in 1936, the medium adopted a nearly-square format to make best use of the circular cathode-ray picture tubes then available - the ratio of sides was 5 units wide by 4 high, '5:4'. It stayed that way, in the UK at least, until after the Second World War, when the service adopted a 4:3 ratio. In other words, a standard TV picture is four units wide to three units high, whatever the actual quoted size of the screen is (which is generally something to do with the length of a diagonal across the visible screen area - the part with an actual picture on it). Another way of putting '4:3' is to say '1.33:1', meaning that the width is about one and a third times the height.
This aspect ratio was based on the common one used for movies made before about 1950. In fact William Kennedy-Laurie Dickson, an employee at the Thomas Edison laboratory, invented the 4:3 ratio back in 1889. His Kinescope used film frames 1 inch wide and 3/4 inches high, and it soon became the standard. In 1941, the NTSC (National Television Standards Commission in the USA) proposed a standard that used the same ratio for television; Britain also moved over to this aspect ratio, and it remained that way until very recently - in fact until the advent of digital television.
But around 1950, the film industry, no doubt worried about the impact of television, began to experiment with a variety of new screen formats with much wider ratios - ratios that were not only beyond the reach of the television of the time, but were also arguably more pleasing on the eye.
It has often been held that widescreen is a good idea because our field of vision is naturally wider than it is high - we have approximately a 30-degree field of vision (and allegedly about 16:9 in aspect ratio), but a 4:3 screen only uses a third of that. In addition, a rectangle with sides in the ratio 1:1.62 has been regarded with special favour since classical times: it is known as the Golden Rectangle and the ratio as the Golden Mean, Golden Ratio or Golden Section, and has traditionally been said to be particularly harmonious.
In fact, the primary new screen ratios that came into use were three: 1.66:1, widely used in Europe and in Disney animations; 1.78:1, the format most widely used for movies in the United States and more usually referred to as 16:9; and 2.35:1, a ratio often used for large scale epics like Lord of the Rings.
The advent of digital television has made both widescreen - 16:9 is the ratio in this case - and high definition (up to almost twice as many lines in the picture, and up to twice as fast) possible.
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