4K TV Technology Explained: What is 4K and Why Should You Care?

Vaughn Highfield June 7, 2020

You may have heard of the terms 4K, Ultra HD, and UHD. These terms have been quickly adopted and used across the globe. Not only are high-end TVs offering 4K UHD resolutions, but other devices that connect to them as well.

4K TV Technology Explained: What is 4K and Why Should You Care?

Sony’s PlayStation 4 Pro and Microsoft’s Xbox One X are trumpeting their ability to run games at 4K resolutions. Sky is pushing its UHD-capable Sky Q platform, while Apple TV offers shows in 4K. Even the Sony Xperia XZ Premium boasts the fact that it has a 5.5-inch 4K screen.

But what is 4K, and how does it differ from Ultra HD and Full HD? Let’s break it down.

What is 4K?

At its most basic functionality, 4K and Ultra HD are four times the resolution of Full HD. A standard Full HD screen will have a resolution of 1,920 x 1,080 (a total of 2,073,600 pixels). Ultra HD and 4K screens have a resolution of 3,840 x 2,160 (a total of 8,294,400 pixels). The more pixels there are, the more detail the picture contains.

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4K HDTVs tend to come in larger sizes than their Full HD counterparts because of the difference between the pixel counts, but even at the same size, you can see the benefits of a 4K image over a Full HD one. Side-by-side, a Full HD image will typically look flatter and softer, while a 4K picture brings out more detail and improved color grading, making the picture sharper and more vibrant.

Aside from resolution, the terms 4K and Ultra HD allow for higher frame rates and better color replication to deliver a more “true-to-life” image. 4K and Ultra HD TVs support 10 and 12-bit color, compared to Full HD’s 8-bit capabilities. This statement means a broader range of colors are available on a 4K screen, and therefore pictures appear more realistic.

A bump in frame rate capabilities to 60 frames-per-second also means smoother action scenes and a sharper picture during frantic movements such as an NFL game or the latest Fast and Furious movie. Current TV is broadcast at 25fps (with films being shown at 24fps), so the bump in frame rate is certainly noticeable and can look somewhat unnatural at first, but it’s definitely an improvement.

What is 4K HDR?

4K HDR (high dynamic range) is yet another variable to understanding 4K, Ultra HD TVs, and 4K content. Not all 4K Ultra HD TVs include HDR capabilities, which is why it’s worth waiting for HDR-enabled sets to come down in price.

HDR is all about the contrast ratio of a picture. It describes the range between the darkest and lightest shades in an image. Think of it as the HDR mode on your phone’s camera, enabling photos to appear more detailed with subtle shadows and bright areas all appearing clearly without impacting the rest of the image. 4K HDR is absolutely stunning in motion.

Technically speaking, you can’t get HDR on Full HD panels, although you will see some retailers marketing their Full HD screens as such. The statement simply means they’ve used some contrast technology to emulate the effects of HDR. By picking up a 4K Ultra HD TV, you’ll be able to snap up HDR technology if the TV you’ve bought supports it.

Where Can You Watch 4K Video?

An increasing number of services are offering 4K content, with Netflix and YouTube being the standard-bearers for the service. Sky offers 4K content through Sky Q and Amazon Prime Video can be streamed in 4K too. If you’re so inclined, you can additionally get 4K Blu-ray players or just grab an Xbox One X with native 4K or the Xbox One S with upscaled 4K resolution. Sony’s PS4 Pro also includes native 4K resolution, but the original PS4 does not.

The BBC network has also dipped its toe into the 4K pool, releasing the entire series of Blue Planet 2 in 4K immediately after each episode was broadcast on BBC One. More than 400 devices were included in the trial, as long as they had a fast enough internet connection to push the pixels. Then, BBC announced it would broadcast the World Cup in 4K.

All of the above services support 4K HDR, but you’ll have to ensure you’ve bought an HDR-capable Blu-ray player and a Blu-ray disc that’s encoded for HDR. Many PS4 Pro games also need an update to display in 4K HDR. The standard PS4 may not support 4K, and Xbox One S upscales it, but they still output in HDR, even for games running at Full HD rather than 4K.