What is 4K?
The headline fact is simple and dramatic: 4K Ultra HD TVs (also known as UHD TVs) deliver four times as much detail as 1080p Full HD, that's eight million pixels compared to two million pixels.
What that means in terms of potential image clarity is more fine detail, greater texture and an almost photographic emulsion of smoothness.
But this is just for starters. Prior to a roll-out of TV services, broadcasters are working out what else they can upgrade under the 4K banner. Some of the biggest names in the video industry including Samsung, LG and Sony have split-off to form another group called the UHD Alliance, which will work to set standards for the new format.
But talk to the engineers steering this 4K broadcast bandwagon and they'll tell you everything spec-wise is up for grabs. If this indicates to you that the 4K standard is anything but set in stone, you'd be correct.
Ultra HD is going to be a work in progress for years to come, but that doesn't mean you should wait for the dust to settle before improving your image.
Difference between Ultra HD and 4K
Technically, "Ultra High Definition" is actually a derivation of the 4K digital cinema standard. However while your local multiplex shows images in native 4096 x 2160 4K resolution, the new Ultra HD consumer format has a slightly lower resolution of 3840 X 2160.
This is one reason why some brands prefer not to use the 4K label at all, sticking with Ultra HD or UHD instead. However, the numerical shorthand looks likely to stick. As a broad brush label it's so much snappier!
How small will 4K Ultra HD screens get?
In the short term, screen sizes are likely to stabilise at 55-inches and upwards. That's because as the screen size shrinks the advantage of having such a pixel dense display starts to diminish. There's also an irrefutable relationship between screen resolution and viewing distances.
While seating will vary from home to home, generally speaking a large 4K TV will provide an upgrade for a smaller 1080p screen. However, the 4K resolution will ultimately be about more than just definition.
How important is HDMI 2.0 to 4K Ultra HD?
HDMI 2.0 is the latest iteration of the HDMI specification. While the existing HDMI 1.4 standard can deliver 4K video, it's limited to 30 frames per second (or 30Hz). While this is fine for most movies, broadcasters are looking for higher frame rates for TV.
HDMI 2.0 increases bandwidth up to 18Gbps and supports 4K Ultra HD at 50/60 fps, with 12-bit 4:2:2 colour (you don't need any special cables for HDMI 2.0 interconnectivity, any current high-speed cable will work).
So should I buy a 4K set now or should I wait?
It depends. If you want the absolute best TV you can get right now and don't mind paying a premium for it, it's a 4K set. If you're buying from one of the top tier manufacturers, you're going to get a good product that's reasonably future-proofed. As we said before, the sets look great. And make sure any set you buy has HDMI 2.0 ports.
On the other hand, if you're price sensitive or want to wait until the content side of the equation is a bit more solved, it absolutely makes sense to wait. You're not missing out on much at the moment. There are incredible values to be found in generously-sized 1080p sets right now. And 4K sets are only going to get cheaper.