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Breaking barriers: The unstoppable advances of television technology

The HD variant of the BBC Test Card, Test Card X.
4 minute read
The HD variant of the BBC Test Card, Test Card X.

Television technology has changed enormously over the course of a lifetime, and it could be just about to change even more swiftly.

In my essentially chaotic and unreliable memory, one thing seems stubbornly fixed: the price of TVs. Remarkably, colour televisions - very different today to how they were in the 1970s - have stayed around the same price. In the UK, the figure etched into my mind is £300.

Of course, that figure doesn't mean they've been the same value. Back in 1970, £300 would have been worth about £6,000 in today's money, and many people - including my parents - rented their televisions because we couldn't afford the cash outlay. And that's without comparing like with like. 1970s TVs were pretty simple compared to today's stunning displays, but they were, for their time, remarkably clever. Imagine being told today that you had to design a colour TV system without digital electronics but with only a mix of valves (tubes) and transistors.

The introduction of color

Colour TV arrived in the UK ten years after the US. Europe took a different path towards today's more universal TV standards. For the post-war years, the standard in the UK was monochrome 405-line. I recollect that it didn't seem at all bad, but with hindsight, it was pretty low resolution. TV production evolved around the primitive cameras at the time, which were often locked off and with flat lighting. The wooden, low dynamic range pictures were unimpressive by today's standards, but the context was that you had to compare the experience with listening to the radio. People sometimes called it "Radio with pictures," which was an entirely reasonable comparison.

One day, I noticed the house opposite had a new TV aerial fitted (I was about seven years old then - and already into TV tech!). It was much smaller than the old VHF TV standard's big "H" designs and heralded the arrival of the UHF 625-line TV. In terms of resolution, it was a big step up. The sharper pictures comfortably filled the larger screens typical of the new UHF sets, but the new TVs were still black and white. But PAL (as opposed to the US NTSC) was not far behind. The new standard solved NTSC's colour fragility by inverting the phase of the colour sub-carrier in every line to be corrected in the television hardware. So errors (caused by the signal bouncing off a passing bus, for example) made an equal and opposite change in successive scan lines, but by averaging each pair of lines together, the error was cancelled out - a bit like how balanced audio connectors work).

In 1967, the village electronics shop put a colour TV in the window. For several hours during the day, there was no programming. Instead, the BBC transmitted a test card. And it was this test signal that was the first colour TV image that I saw. The thing perhaps most unlikely to become a cultural icon - a BBC test card - did indeed become a cultural icon. The reason? It was quirky. In addition to the usual squares, circles and diagonals, it featured a centrepiece that was a full-colour picture showing a young girl in front of a blackboard with some colourful toys. The BBC chose a youngster, Carole Hersee, because she didn't have to wear make-up, which is essential for setting skin tones. The toys and Carole's dress were primary colours; the background was sky blue. And - a touch of genius - on the blackboard was a game of noughts and crosses - ideal for setting up convergence at the centre of the screen.

A thirty-year standard

The PAL 625 line standard was introduced publicly in 1966 and was still doing a great job as recently as 2006, when Full HD was launched in the UK. My first HDTV - by then a 42" Flat screen - was around seven hundred pounds when I bought it in 2007 - but you can buy 4K" sets approximately that size now for £379 - and that's a full Smart TV: massively more advanced than the Sony model I bought in 2007. Four years ago, I purchased an LG 65" 4K TV for £750, which is a remarkable value.

You can't buy a large TV now that isn't at least 4K resolution, and there's a fair amount of 4K content now on the BBC iPlayer. TV fads have come and gone in that time. 3D was great when it worked and in ideal conditions, but 3D really needs a gigantic screen. Avatar in 3D in an IMAX cinema is breathtaking; on a 42" screen from the sofa, you have to ask, "If that's the answer, what was the question?". HDR is awesome if and only if you watch it on a true HDR TV. Many domestic consumer sets claim to be HDR but, in typical conditions, fall far short of that description.

Large OLED screens are really something else. They're saturated and have effortlessly deep blacks. They're not exceptionally bright, but for HDR, the truly black blacks make up for that by extending the dynamic range downwards rather than upwards.

The future of TV?

As for the future: "conventional" TVs aren't going to disappear any time soon. They're too entrenched in our living rooms. You could say that they are the most versatile, most sociable way to watch TV programs. What could be simpler than a screen in the corner of the living room?

But it won't be like that forever. Just look at the early reviews of Apple's Vision Pro. Yes, it's too heavy; it has an external battery with only enough juice for between two and three hours, and it makes you look like a dork (although I think they look science fictiony). But no one I've seen disagrees with the idea that this is how we will watch TV in the future. Imagine having a 150" 3D cinema screen in your living room. Or three of them.

Future versions will be smaller, less obtrusive and will probably look like a pair of glasses. By the time we get to that level of virtuosity with Augmented Reality devices, we will likely be normalised to what Apple calls "Spatial Computing" and what everyone else calls the metaverse.

And it seems a reasonable bet that the demo material will look more like the fauna and flora of Pandora than the BBC's Testcard F.

Tags: Technology History