HDR TV: what is HDR, and what does High Dynamic Range mean for your TV?
If you’re shopping for a new television, you’ve probably noticed manufacturers have stopped touting 4K TVs as the hot new thing. These days, it’s all about HDR — high-dynamic range. Is this just another clever marketing term to make you feel like your TV is outdated? In a word: No. While a standard-issue 4K TV is equipped with more pixels than its HDTV counterpart, an HDR TV can do more with those pixels. But what, exactly, is HDR TV?
‘HDR’ stands for High Dynamic Range, and it is the current big thing for 4K TVs and 4K content. The term originates in photography, and refers to a technique to heighten a picture’s dynamic range – the contrast between the brightest whites and the darkest blacks.
The theory is: the higher the dynamic range, the closer a photograph gets to real life. HDR for televisions is basically the same idea.
Look at the sky. The clouds may be white (or grey in the UK), but there should be definite layers. Around the clouds, you should be able to pick out varying degrees of brightness.
Now look at clouds on your TV. They tend to look flat by comparison, with white levels crushed and layers virtually indistinguishable. There are several reasons for this.
To begin let's look at 4K TVs. 4K TV displays tend to get most of the attention these days, as they produce four times the number of pixels of any HD TV on the market. But is more necessarily better? Do you care how many pixels there are if none of them look any good?
This is where HDR comes in. What HDR does is get more dynamic pictures and quality out of those many, many pixels. What that means for you and your viewing experience is that with an HDR TVs bright whites look brighter, dark blacks look darker, and 10-bit panels are finally able to display the 1 billion colors you've been wanting to see.
So, in short: 4K describes the quantity of pixels, but it's HDR that describes their exceptional quality.
HDR: The basics
What do you need for HDR TV?
Before we go any further, let’s set the stage. To experience HDR on a TV, you need at least two things: A TV that supports one or more HDR formats and the actual content that is produced using one (or more) of those HDR formats. A third, optional part, is a playback device like an Ultra HD Blu-ray player or media streamer that is HDR-compatible.
We say optional because most HDR TVs are also smart TVs, which means they already have apps for services like Netflix and Amazon Prime Video. If you’ve got an HDR TV and that TV can stream HDR content from your favorite streaming service, then that’s all you really need.
Are all HDR TVs equal?
No, not by a long shot. You’ll find HDR TVs at tons of different prices and sizes, and picture quality can vary dramatically. A gorgeous 4K HDR stream of Star Wars: The Empire Strikes Back from Disney+ simply won’t look as good on a $500 55-inch 4K HDR LED TV as it will on a 55-inch 4K HDR OLED TV or QLED TV. Think of it like high-octane gasoline: You can put that same fuel in a Hyundai or a Ferrari, but what the Hyundai does with that fuel is nothing like what the Ferrari can do with it. A high-quality HDR TV will make HDR content look its best.
So what’s so special about HDR anyway?
HDR content (when viewed on a high-quality HDR TV) looks better than standard dynamic range (SDR) content because it is brighter and more colorful. You don’t realize it until you see it next to HDR, but SDR content — the kind we’ve been watching for decades on TV, DVD, Blu-ray or via streaming services — isn’t all that vibrant. HDR ramps up all of the elements we can see so that they’re more lifelike, or at least more like the kind of images you’d seen in a movie theater.
Better brightness, better contrast
HDR increases the contrast of any given on-screen image by increasing brightness. Contrast is the difference between the brightest whites and darkest blacks a TV can display. It’s typically measured as a ratio, e.g. 1:2,000,000, which in this case would mean that that TV is capable of displaying a bright area that is 2,000,000 times brighter than its correspondingly darkest area.
By increasing the maximum amount of nits for a given image, HDR TVs are capable of a higher contrast ratio. LED TVs in particular benefit from this increased brightness, as they can’t show blacks as deep and dark as OLED TVs, so they need to get brighter to achieve the same or better contrast ratios. For more on the differences between OLED and LED TVs.