So what’s all this about 4k TV then?

Early in the twenty tens, we all went digital and were forced to upgrade because the TV services could not be bothered to make it a dual service in the way they had during the introduction of colour. Then you could still use your old Black and White TV until you decided to change to colour in your own time. With the digital changeover, because they had greedily used up every single terrestrial TV channel available, they forced us to jump to their new system with no molly coddling. ‘Buy or don’t get TV sucker!’ they told us grinning evilly. ‘We are going to sell you digital TVs regardless of what you want.’ Whilst we were still reeling from this new system they decided to upgrade the signals to HD TV and although this was, thankfully, optional because they ran the HD service on a parallel channel, it was something else they wanted to get you to go out and buy. Now it is 4k TV.
4k TV, sounds good doesn’t it. Even clearer pictures in greater detail than ever and in close-up we will be able to count the embarrassing hairs on the news reader’s face, where they have not plucked them all. In crowd scenes we will be able to make out the guy right at the back giving the camera the finger and recognise all those people at the footy match who have signed in sick that day. Wonderful. But why so soon? Not only that but, where do you get 4k signals? You can buy a 4k player and some Blu-ray disks claim to be 4k, also you can stream 4k from the Internet if you have fibre but, we have not all changed from DVD to Blu-ray, or afford fibre and they cannot broadcast 4k signals, no room, all the available channels are in use with normal SD and HD TV… Uh Oh!
So, not so much a maybe as a when they shut down all those old SD channels and force us to buy another new and fully compatible 4k TV, fibre Internet, 4k player and upgrade all our movie media once again. So the question now is, how long it will be before the original digital SD service is switched off and we all have to go HD/4k? And it will be a another case of ‘Buy or don’t get TV sucker!’ for a second time. This seems all the more likely, because now, they are pushing 4k TV so damn hard. So what is 4k anyway?

Note; most of what follows is about the UK TV services.  There are a number of differences in other national standards.  In many countries the majority of viewers use cable unlike the UK wherer the majority use broadcast signals. 

Well a long time ago we had 405 line TV, which was better than the original 1920s Baird blur but not special, it just seemed it at the time. 

Then in 1964, it got better when we upgraded to 625 lines and 1969 to colour. With the introduction of digital in the 2010s the basic service, SD TV, became 576 lines, which sounds as if it is a little less than the old 625 line system. Actually on that old analogue system you only had a little over 300 lines in practice so SD looks sharper than the old analogue signal. Almost immediately they introduced HDTV. HD comes in two flavours, 720 lines and 1080 lines. There is also the option for interlace, i or p, which is not worth worrying about here. 720 HDTV is the kind of picture you get on an ‘HD ready’ TV and is a kind of poor man’s HDTV, whilst 1080 lines is full HD and only displayed properly on a full HD TV, but will show 576, or 720 pictures if that is all it gets. So, if full HDTV is 1080 lines, just over one thousand, then you may assume that 4k TV is going to have four thousand lines. Wrong.
If you look at the full HD picture, it is one thousand and eighty lines down the screen. You could count them if you have a magnifying glass. HD televisions have a wide screen, making the width of the picture wider than the height. This means that on a picture that has 1080 lines down, there is room for approximately two thousand image picture elements (pixels or dots if you prefer) across the screen and so 1080 HD could be called 2k. Now I bet you have guessed it! 4k is not four times the definition of full HD, it is only twice as good and has around two thousand vertical lines and four thousand pixels across, hence the deliberately misleading 4k. What a disappointment, I bet you won’t be rushing out to get a new 4k TV after all.