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Everything you need to know about 4K TV color: HDR, WCG and 10-bit color

by on October 17, 2016
 

Stephan Jukic – October 17, 2016

Like their resolution, backlighting technology and their smart TV features, color in today’s 4K TVs has also become more sophisticated and as a result more complicated for consumers to understand. The main reasons for this are the different color standards you’ll see thrown around about 4K TV color and which TVs come with what and thrown into this mix is all sorts of possibly mysterious technical jargon such as 10-bits, 8-bits, HDR color, quantum dots, phosphor coloring and so on.

Obviously enough, the mix of all these things can get downright confusing even for 4K TV buffs, let alone for consumers who just want a great 4K TV without saturating themselves with all sorts of details.

However, if you are one of these 4K TV buyers who wants that great TV, it is a good idea to know at least the most important stuff about how color works and which TVs deliver it at its absolute best. That’s what we’re going to tell you here with as much clarity and simplicity as possible. Here are the most important things you should know about 4K TV color today.

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What exactly do you mean by 4K TV color?

You see, 4K TVs don’t all come with the same color coverage or even color technology across the board. There are older color standards for older ultra HD Televisions, which are basically the same as those found in most HDTVs and newer standards which are found in the latest and best 4K TVs with high dynamic range.

The older color standards also cover contrast levels, black performance and brightness and the TVs which can only display these are called SDR 4K TVs, just as the vast majority if not all models of non-4K UHD televisions can be considered SDR TVs.

4K TV color in these older TVs with only SDR display capacity was of a weaker sort with more limited color space coverage and color depth and this is something which 4K TV manufacturers and 4K content creators sought to change by developing what is now called HDR color display and standards, which are made up mainly by the standards of wide color gamut (WCG) and 10-bit color (as opposed to the 8-bit color of SDR content and TVs). This enhanced 4K TV color is what we’re mainly talking about here and it’s what offers the absolute best in today’s 4K TV display technology.

pixels which support enhanced color and HDR are commonly called "Better Pixels"

Pixels which support enhanced color and HDR are commonly called “Better Pixels”

If you want the best possible 4K TV with the most future-proof display performance for the next generation of HDR 4K content, an enhanced color 4K TV is what you need to get your hands on. We also cover these in much greater detail throughout our guide to high dynamic range (HDR), found here.

Now you know what we’re going to discuss when we refer to 4K TV color but you’re probably still confused about what all the jargon in the previous paragraphs means. After all, what is wide color gamut, 10-bit color, SDR, HDR and so on? These things are what we’re going to cover now, one by one.

What is SDR color?

As we said, SDR color represents what you’ll find in today’s HDTVs and in many of the older 4K TVs still sold on the market (mainly from early 2015 and 2014 or before) But what exactly is it? Quite simply, it is digital TV color without the latest enhancements such as wide color gamut and 10-bit color depth. No 4K TV with SDR (standard dynamic range) color specs can display 4K HDR content and no such 4K TV can offer the full depth of enhanced color that has been mastered into the latest and best sources of 4K UHD HDR content.

A 4K TV with SDR color can only display a total of 16.7 million colors because it offers only 8-bit color depth and only display a limited part of the whole visible color spectrum because it doesn’t offer wide color gamut according to the best 4K TV display standards available today for high dynamic range in particular. The current benchmark for these wide color standards is called DCI-P3 (Digital Cinema Initiative-P3) and SDR TVs without WCG can display no more than maybe 80% of this color space. HDR 4K TVs with Wide Color Gamut can on the other hand display more than 90% of the same color spectrum space.

What is HDR color?

HDR color is found only in the most modern and generally best 4K TVs released in mid to late 2015 and in all of 2016. It is increasingly found in a growing percentage of all 4K TVs released by each of the major television makers today and it is what covers the essence of “enhanced” color as you the consumer need to understand it.

Full enhanced HDR color basically consists of wide color gamut and 10-bit color as we described them above and it’s found in all the flagship 4K TVs of late 2015 and all of 2016 and also found in many of the mid-range and even budget 4K TVs for 2016 in particular. Most 4K TVs will come with full HDR color by 2017 as far as we can predict and this is a wonderful thing to behold because the color enhancements delivered by wide color gamut and 10-bit color are huge when compared to what you’d see with regular SDR display and 8-bit color.

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What about HDR color and HDR Contrast?

On the other hand, not all HDR 4K TVs come with HDR color. You see, as we cover much more fully in our HDR standards guide, high dynamic range is about both color enhancements and greater range of contrast steps between enhanced dark levels and enhanced levels of peak brightness. Thus, a 4K TV with HDR can have either both or just one of these pillars of high dynamic range. Some 4K TVs can come with HDR contrast enhancements but lack HDR color enhancements and other 4K TVs can come with exceptional HDR color performance but lack certain aspects of HDR contrast performance.

The best possible color performance in a 4K TV will however come from HDR TVs which offer both enhanced color and exceptionally high levels of peak brightness, deep local dimming and black performance. This is because brightness, black performance, local dimming and contrast range are integral to making the colors they work around stand out more vibrantly and realistically. Our guide to 4K TV backlighting goes into a lot of detail about how backlight technology in 4K TVs enhances overall picture quality.

However, all premium 2016 4K TVs such as Samsung’s KS-Series SUHD TVs, Vizio’s P-Series 4K TVs and Sony’s XBR-ZD and XBR-XD 2016 4K TVs all come with both HDR color and HDR contrast performance.

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What does 10-bit color mean?

Now to define just what the 10-bit color we’ve been referring to all this time means. Quite simply, it defines the range of possible color values per RGB subpixel in each pixel of a 4K TV display. All 4K TVs create their entire range of colors through the use of Red, Green or Blue (RGB) sub-pixels inside each individual pixel on their screen. White is created by activating all three sub-pixels at the same time in a certain way though with some 4K TVs there is also a pure white sub-pixel and in a rare few 4K TVs there are also yellow sub-pixels. For the sake of simplicity however, the vast majority of 4K TVs come only with the three RGB sub-pixels per full pixel. Each of their subpixels can either be 8-bit or 10-bit. In an 8-bit pixel, the colors it represents (red, green and blue) can be varied to 256 different shades each. In a 10-bit TV display, each sub-pixel can on the modified to 1024 different tones of teach RGB color (again, either red, green or blue).

Now, to really see just how much impact these two extra bits offer in a 10-bit HDR 4K TV color display, we need to multiply all the primary color mixes possible by each other. Thus, for an 8-bit 4K TV, you get 256 x 256 x 256, amounting to a total of 16.8 million colors and in a 10-bit TV, you get 1024 x 1024 x 1024, amounting to 1.07 billion color possibilities per pixel.

This is why a 10-bit TV panel or a 4K TV panel which simulates 10-bit display effectively (as most panels actually do without truly offering 10-bit color depth) can create a far richer, smoother quality of color for 10-bit HDR content. The effect created is one of much better realism and much better color accuracy if you’re using an HDR TV to watch content mastered with 10-bit color depth.

10bit-fg

What does Wide Color Gamut mean?

Wide color gamut, or WCG, is a bit of different thing from 10-bit color depth. It represents all the possible colors of a color gamut that a 4K TV can display. Thus, a 4K TV with HDR color can show a much larger area of the total visible color spectrum than a SDR TV without enhanced color.

The specific color gamuts most often used to denote what means wide color gamut and what means narrow color are Rec.709, DCI-P3 and Rec.2020. The Rec.709 color space is what was used for years and still is used as the maximum color coverage of HDTVs and most SDR broadcast and other digital media content. However, Rec.709 is only a smaller part of the bigger DCI-P3 color space, which is itself a smaller part of the newest digital enhanced color broadcast space known as Rec.2020. No TV in existence today shows full Rec.2020 coverage but all HDR 4K TVs with enhanced color show at least 90% of the DCI-P3 color space and more than 100% of the Rec.709 color space. A 4K TV which shows 90% or more of DCI-P3 color is however only showing something around 60% of the Rec.2020 color spectrum.

The bottom line for wide color gamut is that it’s a key part of HDR color in a 4K TV and that this technology is what will let the television you buy fully display the wide spectrum of colors which have been mastered into the high dynamic range content that’s available from sources like 4K Blu-ray, Netflix, Amazon Prime and other streaming content providers.

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So where does HDR and SDR content fit into the picture (literally)?

HDR color through WCG and 10-bit color depth only apply in your 4K TV when it comes to watching content with HDR color support (WCG and 10-bit color) mastered into it during production. Today’s 4K HDR TVs with enhanced color won’t use their full color enhancement capacities if they’re displaying the vast majority of content which is still 8-bit and SDR in its color gamut coverage.

This is unfortunate but it is at least changing as more HDR content gets produced in 4K resolution for the growing percentage of HDR 4K TVs. Also, TV makers themselves are working on new upscaling technologies for the best 4K TVs sold today so that they not only upscale non-4K video to look sharper and more ultra HD-like (as all 4K TVs of both the HDR and SDR type already do), but also upscaled SDR video from broadcast, disc and streaming sources to benefit from some of the built-in 10-bit and WCG color capacities of these 4K TVs. Two notable examples of premium 4K TVs which are doing this include Sony’s latest Z9D HDR models, Samsung’s 2016 SUHD TVs and LG’s 2016 OLED HDR televisions like the G6, E6 and C6 4K TV.

This HDR-upscaling effect is still far from perfect but it is working to at least partly improve the quality of content with SDR color formatting as it renders on a 4K HDR TV display.

However, for now, the absolute best entertainment you can get if you want your TV to really show off its enhanced HDR color capacity is native HDR 4K video from a 4K Blu-ray disc or Netflix and Amazon’s selections of streamed HDR programming.

Entertainment such as 4K Blu-ray discs can be viewed in enhanced color on HDR 4K TVs

Entertainment such as 4K Blu-ray discs can be viewed in enhanced color on HDR 4K TVs

What about Quantum dots, phosphor coatings and all those other buzzwords?

If you’re looking to buy a 4K TV with high quality enhanced color, you’ll also hear a lot about the presumed benefits of technologies like quantum dot color and color enhancing phosphors in premium 4K TVs from Samsung, LG (quantum dots) and Sony (Triluminos Display, which means colored phosphors on TV backlight LEDs).

All of these technologies are basically additional means by which TV manufacturers make their 4K HDR TVs display wide color gamut and 10-bit color even more effectively and precisely. A 4K TV with enhanced color doesn’t need quantum dots of Triluminos Display to offer wide color gamut and 10-bit color but these types of technologies allow the TV to offer even better color saturation and color tone variation than would be possible without them.

 

 

Quantuim Materials for a Samsung QD TV

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Quantum Dot Materials for a Samsung QD TV and Triluminos Display for Sony 4K televisions

What about future-proofing my 4K TV for upcoming color standards?

Most of the 4K HDR content that already exists has already been mastered to display wide color gamut and color depth which far exceed what even the best 4K TVs of 2016 can actually offer. In this one way, what little HDR content that exists is already far ahead of the much more commonly seen technology of HDR color 4K TV display in its specs.

Thus, while even the best 4K TVs of 2016 can only manage 10-bit color depth and 96% DCI-P3 color space coverage for WCG, HDR 4K video formatted for the Dolby Vision HDR standard is already capable of displaying at 12-bits and better than 100% DCI-P3 wide color gamut coverage, if it were only to be played in a 4K TV capable of showing these sorts of visuals. The growing percentage of HDR entertainment content that gets created will come with the same capabilities. What this means is that the most future-proof 4K TVs today for the most advanced content sources which already exist are those with full HDR color which includes 10-bit color depth and WCG, as well as full HDR contrast specs.

On the other hand, the vast majority of broadcast, hard disc and even streaming digital video content isn’t HDR at all and is in fact formatted to only display in 8-bit color. Thus even today’s 4K TVs are capable of more than most content can render on a screen. In other words, while you should absolutely get a 4K TV with Full HDR color, don’t worry about it being obsolete any time soon as far as the vast majority of your TV watching is concerned.

Okay so what is the bottom line?

The bottom line is this. 4K TV color can be of the more narrow SDR kind described above or it can be of the HDR color type that’s increasingly being formatted into the latest digital video entertainment. If you can get your hands on a 4K TV with full HDR, then do so, because it will offer you the best quality for the latest color and contrast mastering in today’s most recent HDR movies and TV shows. However, don’t obsess too much about color beyond this either since home entertainment video itself still has plenty of catching up to do before most of it is 10-bit or WCG-capable.

samsung-suhd-tv-04

Story by 4k.com

14 comments
 
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  • George Yeoh
    October 17, 2016 at 11:29 pm

    Very useful article that is informative for the lay person. Well done Stephen! I was an early adopter with a Sony 4K and hate the “you do not have an HDR TV” message when I play 4K Blurays on my Samsung. I will wait until prices came down for the new generation 4K HDR enabled TVs.

    Reply

  • Richard Harrison
    October 27, 2016 at 12:38 pm

    Fantastic article breaking all of this, as you say, complex material down.

    I have pre-ordered a PlayStation 4 Pro and I’m horrified to find out that my 4KTV does have HDR but of the 8-bit variety. I’m considering cancelling my order as PlayStation have stated that the TV requires HDR10 compatibility.

    Given your expertise, and know how, will my TV that is compatible with HDR 10 (in that it can read the signal rather than output it) actually display anything in HDR?

    Cheers

    Reply

  • Erf
    December 1, 2016 at 5:31 am

    Thank you Stephen, this is very comprehensive and easy to understand blog (despite the technical nature of evolving 4K displays) ended up buying the XBR 75X 850D that gets me the wider color gamut but still allows me to make my mortgage payments

    Reply

  • Ishan
    December 18, 2016 at 8:40 am

    does the LG B6 have the HDR upscaling feature?

    Reply

  • Deneteus
    December 19, 2016 at 3:19 pm

    Article doesnt cover WCG and 10 bit when it comes to gaming. How does this affect current gen gaming? PS4 Pro and Microsofts 10 bit.

    Reply

    • Stephen
      Stephen
      January 31, 2017 at 9:44 pm

      Hello there Deneteus, these two color standards will affect gaming in much the same way that they affect movie/TV HDR content. They will create a much more vibrant, smoothly textured color saturation and variation in the HDR games you play.

      Reply

  • Sabareswar T C
    December 29, 2016 at 7:59 am

    Dear Mr. Stephen

    Could you please Enlighten me on the following
    my Tv says it supports 10 bit and 12 bit color depth in the HDMI 3 port
    However let me enumerate the color spaces it works..

    8 bit 10 bit 12 bit
    Y Cb Cr – 4:2:0 Y Cb Cr – 4:2:0 Y Cb Cr – 4:2:0
    Y CB Cr – 4:2:2 Y CB Cr – 4:2:2 Y CB Cr – 4:2:2
    Y CB Cr – 4:4:4 ——————– ——————–
    R G B – 4:4:4 ——————– ———————

    Does my 4k tv supports HDR ….?
    If no then will I be able to see the difference between non-HDR and HDR enabled videos at-least by a few scales …
    I am not asking whether the present day native HDR (say life of pi 4k HDR ) will flawlessly play on my tv…
    I am asking whether I would notice any significant difference between “life of pi 1080p fhd” from my set top box and my 4K UHD blu ray life of pi from xbox one s…?

    Reply

    • Stephen
      Stephen
      January 31, 2017 at 9:43 pm

      Hello Sabareswar, Could you please let me know what kind of 4K TV you have,the model?

      Also, From what you show me, your 4K TV likely does support HDR and I’m guessing it might even offer Dolby Vision HDR support from looking t this.

      As for whether 4K with HDR wide color gamut and 10-bit color enabled on a 4K TV while watching a movie with HDR mastering looks better than normal FHD SDR video, yes, absolutely and particularly on 4K TVs with full HDR support for both color and contrast quality/black levels and high brightness.

      Reply

  • Allen West
    January 7, 2017 at 8:10 am

    Been a senior member on AVS for ten years and your article is one of the best I’ve read on this subject matter that get totally misconstrued on the forums.

    For years I’ve witnessed arguments and misunderstanding’s of Native Bit Rate of a Panel like Ten vs 8 and (12-14) Bit Processing which I believe is software based and more marketing fluff than anything else – just as often I witness members seeking a Rec. 2020 panel and none exists. I don’t believe all the elements to = a Rec. 2020 panel will ever be certified as it requires so many elements external to the panel itself to meet the “GOAL” by the time it gets close don’t you think the bar will have been raised?

    Reply

    • Stephen
      Stephen
      January 8, 2017 at 1:23 pm

      Thank you very much for the compliment Allen. As for your other points. Bit processing technology using things like dithering can indeed simulate 10-bit color in 4K TVs quite effectively. In this case, the terminology describes something more than just marketing fluff. This isn’t often the case, as we know with fluffed up motion “enhancement” rates in many 4K TVs but with 10-bit color the simulation of added color values is effective.

      As for Rec.2020 panels existing eventually. I’ve learned to never laugh at the future of an technology since creative development can surprise you with how it manages something that previously seemed very difficult to pull off. We’re already hitting 85% of Rec.2020 color space rendering capacity in wide color gamut and within 2 to 3 years I think we’re going to see the arrival of simulated or native 12-bit 4K TVs with wide color gamut that goes above 100% of the DCI-P3 space. The bar might get raised beyond that but not by too much since the visible color space is literally limited out beyond what Rec.2020 covers.

      Reply

  • YoloSwag
    January 14, 2017 at 5:43 pm

    Great article for those looking for a future proof 4K TV.

    Just a suggestion – you could add some more about each manufacturer’s technology and how it differs.

    To anyone out there looking to buy a 4K HDR TV – Don’t just look at it online and buy it. Go to a nearby appliance store to see it for yourself. I like Sony and like their triluminous displays but when you put them next to LG’s OLED TVs, it’s just so far, I like the OLED better than Samsung’s Quantum Dot thing.

    I’d say wait for 2017 models and don’t do a rush buy. You might regret it.

    Reply

  • Ben P
    February 7, 2017 at 5:14 am

    Thanks Stephen, your article helped me with better understanding. Here’s a question for you that seems odd to me. Yesterday I spoke with ‘Abe’s of Maine’ that is seling the Samsung 9800 and advertised as low as $ 2399.00 on their website. I rushed to order and they told me that there are two versions of the Samsung 9800 !!!, this cheaper version is made in China and is a 4-bit panel version. They offered me instead the same model, with a 10-bit panel made in Mexico for a slightly higher price ($2800.00). This difference in a same model seems dubious to me. I called Samsung for verification, but the CR could not verify anything about two models in existence. Google searches do show that the 9800 model is a 10-bit. But the point that ‘Abe’s of Maine’ also has a 4-bit made in China version is troubling to me, in that how would I know that I am getting the 10-bit. Could you please speak to this dual model (call Abe’s), and let me know is there’s a catch somewhere that one needs to be aware of. THANKS.

    Reply

    • Stephen
      Stephen
      February 7, 2017 at 9:51 am

      I did a bit of research on this Ben and quite frankly what I believe is that you’re being snowballed here by the store. They’re trying to sell you a grey market refurbished KS9800 with a completely different panel design that has nothing to do with the intended quality of the 10-bit panel that this model normally comes with. The KS9800 is a full-array 4K 10-bit wide color TV with some of the best HDR in existence among 2016 4K TVs. It will obviously enough not be too cheap and if you’re being offered one for a ridiculous discount and a so-called 4-bit panel, stay away from it if you want the quality of the TV as it’s supposed to be. There’s no point in buying it otherwise. Better to just go for a cheaper but still great HDR 4K TV of a lower caliber like the KS8000 or a Vizio P-Series.

      Reply

      • Ben P
        February 7, 2017 at 7:17 pm

        Thanks Stephen, appreciate your response. I spoke with the store again, before your response and they have given me these assurance: The higher priced KS9800 10-bit model, is a US model made in Mexico that I can registered with Samsung for the first year warranty, there after I can purchase an extended four year warranty from a main stream insurer, which should have me covered. What am I missing here ? Would Samsung allow a refurbished grey market TV be registered for warranty ?

        Reply

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