HDR TV & movies
While the arrival of 4K promises us more pixels than ever before, it’s HDR you have to thank for improving the quality of the pixels along the way. Here’s what you need to know
When you think of the next generation of TVs, your mind immediately goes to 4K, and with the new and improved format offering four times the amount of pixels as regular Full HD it’s easy to see why.
4K is certainly a big step forward in the detail stakes, but there’s another technology that’s arrived alongside it that offers almost as big a step forward for picture quality. That technology’s name? High dynamic range.
While 4K (also known as Ultra HD) offers more in the way of pixels, HDRs focus is on improving the quality of individual pixels. If you’re buying a new 4K TV that doesn’t have it, you’re missing out on almost half of the benefits of the next generation of television.
What is HDR?
Thankfully, the benefits of HDR mean that it’s quickly become an essential inclusion in most new televisions. So what is HDR, and how do you make sure you’re getting the most out of it?
It’s got a dull name, but the effect it creates is actually very impressive. HDR allows the pixels of your television to get both darker and lighter than they could previously.
That means dark parts of the image will get truly black rather than simply a muddy grey, and whites can get so bright that they add an extra sparkle to an image that would otherwise be lacking.
The number one benefit that this gives you when you watch an HDR screen is detail.
Imagine a campfire scene from one of your favourite Westerns. The fire itself is likely to be nice and bright, while the world around it is bathed in shadow.
This sort of situation is a nightmare for an SDR TV. If it wants to show off the detail in the fire, then it will have to adjust itself to be darker overall, to bring the fire’s brightness within the range it’s capable of displaying. Doing this, however, means that most of the shadows will be too dark for the TV to display, and all their detail and depth will be lost.
Try the opposite tactic and you’ll lose just as much detail in the bright fire, which will become a blurry mess. Sure, you’ll be able to see what’s going on in the shadows, but at what cost?
By increasing the spectrum of brightness that a TV is capable of displaying, then detail can be preserved in both incredibly bright and incredibly dark parts of an image at all times.
But it’s not just increased levels of detail that HDR has to offer. A wider range of brightnesses means that images have the appearance of having more depth.
Imagine, in this instance, a TV displaying a picture of a bowl of fruit. There might be a bit of a reflection on the waxy surface of an apple or grapes, while between the fruit are shadows created by the light around them.
By increasing the darkness of the shadows between them, and increasing the brightness of any reflections, HDR lets you see each piece of fruit as a 3D object, rather than just a picture on a screen.
Clues like these trick our brains into thinking objects have depth without the need for gimmicky 3D TVs or glasses (which, thankfully, don’t appear to have survived into the 4K era).
That said, there are a couple of things to watch out for to make sure you’re getting a TV that can make the most of HDR content.
Many manufacturers claim that their TV offers HDR because it’s able to go a little brighter and a little darker than their previous versions. But proper HDR has a strictly defined level of brightness and darkness that it needs to hit. The standard (as defined by the UHD Alliance) states that to be classed as HDR an LCD TV must be capable of going as bright as 1,000 ‘nits’ (a measure of brightness) and as dark as 0.05.
Like every bit of tech, it can be easy to obsess over the numbers, and these rarely tell the full story. If you want to ensure your next TV meets the baseline standard of HDR, then look out for any mention of HDR10 compatibility. Some manufacturers will use other terms such as HDR+, HDR Pro and HDR Premium to avoid being explicit about compatibility, but HDR10 is a standard with specific requirements, and if a TV has it then you know what you’re getting.
In an ideal world you’d also look out for the UHD Premium logo – a certification that lets you know that a TV has tech that constitutes the next generation of TV – but unfortunately not every TV manufacturer is using it, and as such it’s not as reliable an indicator as it seems. Different TVs achieve their HDR in different ways, and these can vary wildly in effectiveness.
Which TVs do HDR?
OLED TVs produce arguably the best HDR images. Whereas LCD TVs have to rely on an imprecise backlight shining through the pixels to provide enough light for the image, the light from an OLED TV comes from the pixels themselves.
This means that when a pixel needs to be black it can turn off entirely, and produce literally no light at all - essentially a perfect black. In contrast, the best an LCD can do is to turn off the backlight behind the pixel, and since no LCD can do this on a per-pixel basis, there’ll always be a little light creeping through that results in a black closer to grey.
After years of dominance by LG, 2017 saw major manufacturers jump on the OLED TV bandwagon. LG still produces the most diverse models, but the B7 and C7 are great budget OLED sets. They have exactly the same picture quality as LG sets several times their price, though they have weaker sound.
Other OLED manufacturers tend to be more expensive, but each has a little secret sauce they use to spice up their offerings. Sony’s A1E is great at upgrading SDR content to HDR, while Philips equips its OLED TVs with Ambilight, a technology that complements the images on screen by illuminating the wall behind your TV.
That said, there are still some very strong LCD performers out there. Although OLEDs are capable of going especially dark, they struggle to get as bright as LCDs. You get better shadows, but less sparkle from the bright parts of an image.
The light from an OLED TV comes from the pixels themselves