Updated

Peak Brightness of TVs
Max luminosity and HDR highlights

What it is: How bright the screen can get. Measured with local dimming and over HDR signal (if supported).
When it matters: Bright living rooms; bright objects; HDR content.
What it is: How bright the screen can get. Measured with local dimming and with SDR content.
When it matters: Bright living rooms; bright objects; SDR content.

Peak brightness refers to the maximum luminance of a TV. A higher peak brightness means the TV can make the picture look brighter, which can help with visibility in a room with lots of light, or to make small highlights in the picture look good (which is important for HDR).

For these tests, we take measurements of the peak brightness of a few white rectangles, each covering different sizes on the screen. The measurements are in cd/m2, also known as ‘nits.’

Update 2017/03/10: We have added the SDR peak brightness and renamed our existing peak brightness to HDR peak brightness. This was needed since we discovered that some TVs get brighter while in 'HDR mode' than with standard 'SDR mode', and we wanted to be able to rate both separately. This is especially important for normal TV content, like cable TV or OTA, since at the moment there is no HDR available for this specific content. We have also created a new test named 'Real Scene Peak Brightness' for each of the SDR and HDR peak brightness ratings. We use this new test to measure the maximum peak brightness a TV can obtain while displaying some more traditional video content, instead of displaying our peak brightness patterns.

Test Results

When it matters

High peak brightness (400.2 cd/m2)
Low peak brightness (189.3 cd/m2)

Peak brightness matters in any situation in which you want the picture, or part of the picture, to get really bright. Usually, this applies to one of two scenarios:

  • Watching TV in a bright room: If the picture is too dim in a bright room (especially with sunlight), it will be difficult or impossible to see details in the picture.
  • Watching HDR video: One of the main draws of HDR is brighter highlights. Learn more about HDR.

If either of those usages is a concern of yours, it will be important to get a TV that has high peak brightness; look to the pictures above to see how big of a difference it makes. If you only watch non-HDR media in a dark room, you don’t need to worry about these tests.

We consider a TV that gets to over 400 cd/m2 in our 50% window of the SDR peak brightness test to be bright enough that the TV will look good in a bright room, and one that brightens to over 1000 cd/m2 in our 2% window HDR peak brightness test to be good for HDR highlights.

Our tests

HDR Real Scene Peak Brightness

What it is: The maximum luminosity the TV can obtain while playing a movie or while watching a TV show. This scene was selected to represent a more realistic movie condition. All measurement are made with the TV set to be as bright as possible, but with a 6500k white. Measured with local dimming, max backlight and over HDR signal. Scene: here.
When it matters: When watching movies or watching TV show in HDR.

Our HDR Real Scene Peak Brightness test measures the maximum brightness of a white rectangle displayed on an area covering approximately 2% of the TV’s screen, but with more realistic content instead of with a test pattern. This provides an idea of how bright a small highlight – the sun, a distant explosion, etc. – might look onscreen, which is quite important for HDR media.

For this test, we do the following

  • Set the TV’s lighting to the maximum value
  • Activate local dimming at max (if available)
  • Play our HDR test clip

Next, we then use a luminance meter (Minolta LS-100) to measure the brightness of the top-left white lamp.

SDR Real Scene Peak Brightness

What it is: The maximum luminosity the TV can obtain while playing a movie or while watching a TV show. This scene was selected to represent a more regular movie condition. All measurement are made with the TV set to be as bright as possible, but with a 6500k white. Measured with local dimming, max backlight and over SDR signal. Scene: here.
When it matters: When watching movies or watching TV show in SDR.

Our SDR Real Scene Peak Brightness test measures the maximum brightness of a white rectangle displayed on an area covering approximately 2% of the TV’s screen, but with more realistic content instead of with a test pattern. This provides an idea of how bright a small highlight – the sun, a distant explosion, etc. – might look onscreen.

For this test, we do the following

  • Set the TV’s lighting to the maximum value
  • Activate local dimming at max (if available)
  • Play our SDR test clip

Next, We then use a luminance meter (Minolta LS-100) to measure the brightness of the top-left lamp.

HDR peak 2% Window

What it is: The maximum luminosity, even if only maintained for a short time, of a white square covering 2% of the screen, with the TV set to be as bright as possible. Measured with local dimming and over HDR signal (if supported).
When it matters: Bright highlights, present on screen for a short time; especially for HDR content.
Good value: > 1000 cd/m2
Noticeable difference: 100 cd/m2
2% window test pattern

Our HDR 2% window test measures the maximum brightness of a white rectangle displayed on an area covering 2% of the TV’s screen. This provides an idea of how bright a small highlight – the sun, a distant explosion, etc. – might look onscreen, which is quite important for HDR media.

For this test, we do the following

  • Set the TV’s lighting to the maximum value
  • Activate local dimming at max (if available)
  • Send HDR metadata (if supported)

Next, we use the CalMan 5 for Business calibration software to display a white rectangle that takes up 2% of the TV’s screen, with the rest of the screen left black. We then use a luminance meter (Minolta LS-100) to measure the brightness of the white.

SDR peak 2% Window

What it is: The maximum luminosity, even if only maintained for a short time, of a white square covering 2% of the screen, with the TV set to be as bright as possible. Measured with local dimming and over SDR signal.
When it matters: Bright highlights, present on screen for a short time; especially for SDR content.
Good value: > 400 cd/m2
Noticeable difference: 100 cd/m2

The SDR peak 2% window is done in the same way as the HDR 2%, but instead of measuring the maximum luminance with an HDR signal, it is measured with a standard SDR signal. The SDR peak luminosity of some TVs is sometimes lower than what they can reach with an HDR signal. Since most of the TV content is in SDR, this test is more representative of the level of brightness available while watching standard movies, TV shows, and sports events.

HDR sustained 2% Window

What it is: The lowest maximum luminosity (usually after it has stabilized) of a white square covering 2% of the screen, with the TV set to be as bright as possible. Measured with local dimming and over HDR signal (if supported).
When it matters: Bright highlights, persistent throughout a scene; especially for HDR content.
Good value: > 1000 cd/m2
Noticeable difference: 100 cd/m2

The sustained 2% window is done in the same way as the peak, but instead of measuring the maximum luminance, we measure the lowest luminance. The peak luminosity of some TVs, like Samsung or Sony, varies in time, so this is the lowest luminosity we measure, without changing anything.

SDR sustained 2% Window

What it is: The lowest maximum luminosity (usually after it has stabilized) of a white square covering 2% of the screen, with the TV set to be as bright as possible. Measured with local dimming and over SDR signal.
When it matters: Bright highlights, persistent throughout a scene; especially for SDR content.
Good value: > 400 cd/m2
Noticeable difference: 100 cd/m2

The SDR sustained 2% window is done in the same way as the HDR sustained 2%, but instead of measuring the lowest luminance with an HDR signal, it is measured with a standard SDR signal. The peak luminosity of some TVs, like Samsung or Sony, varies in time, so this is the lowest luminosity we measure, without changing anything.

HDR peak 10% window

What it is: The maximum luminosity, even if only maintained for a short time, of a white square covering 10% of the screen, with the TV set to be as bright as possible. Measured with local dimming and over HDR signal (if supported).
When it matters: Bright objects, present on screen for a short time; especially for HDR content.
Good value: > 1000 cd/m2
Noticeable difference: 100 cd/m2
10% window test pattern

Our 10% window test measures the maximum brightness of a white window displayed on 10% of the TV’s screen. This provides an idea of how luminous a single, medium-sized, bright object – a sunrise, a small fire, etc. - might look on the screen. As with the 2% test, this result is important for seeing how good a TV is for HDR media.

We use the same test process for this test as we do for the 2% test, except we display a white rectangle that takes up 10% of the screen.

SDR peak 10% Window

What it is: The maximum luminosity, even if only maintained for a short time, of a white square covering 10% of the screen, with the TV set to be as bright as possible. Measured with local dimming and over SDR signal.
When it matters: Bright objects, present on screen for a short time; especially for SDR content.
Good value: > 400 cd/m2
Noticeable difference: 100 cd/m2

The SDR peak 10% window is done in the same way as the HDR 10%, but instead of measuring the maximum luminance with an HDR signal, it is measured with a standard SDR signal. The SDR peak luminosity of some TVs is sometimes lower than what they can reach with an HDR signal. Since most of the TV content is in SDR, this test is more representative of the level of brightness available while watching standard movies, TV shows, and sports events.

HDR sustained 10% Window

What it is: The lowest maximum luminosity (usually after it has stabilized) of a white square covering 10% of the screen, with the TV set to be as bright as possible. Measured with local dimming and over HDR signal (if supported).
When it matters: Bright objects, persistent throughout a scene; especially for HDR content.
Good value: > 1000 cd/m2
Noticeable difference: 100 cd/m2

The sustained 10% window is done in the same way as the peak, but instead of measuring the maximum luminance, we measure the lowest luminance. The peak luminosity of some TVs, like Samsung or Sony, varies in time, so this is the lowest luminosity we measure, without changing anything.

SDR sustained 10% Window

What it is: The lowest maximum luminosity (usually after it has stabilized) of a white square covering 10% of the screen, with the TV set to be as bright as possible. Measured with local dimming and over SDR signal.
When it matters: Bright objects, persistent throughout a scene; especially for HDR content.
Good value: > 400 cd/m2
Noticeable difference: 100 cd/m2

The SDR sustained 10% window is done in the same way as the HDR sustained 10%, but instead of measuring the lowest luminance with an HDR signal, it is measured with a standard SDR signal. The peak luminosity of some TVs, like Samsung or Sony, varies in time, so this is the lowest luminosity we measure, without changing anything.

HDR peak 25% window

What it is: The maximum luminosity, even if only maintained for a short time, of a white square covering 25% of the screen, with the TV set to be as bright as possible. Measured with local dimming and over HDR signal (if supported).
When it matters: Bright rooms; bright objects in HDR video.
Good value: > 1000 cd/m2
Noticeable difference: 100 cd/m2
25% window test pattern

Our 25% window test measures the maximum brightness of a white rectangle displayed on 25% of the TV’s screen. In practical terms, this would likely be experienced as a sizeable portion of brightness – the exit from a tunnel, a bright blue sky, etc. – in a picture otherwise filled with darker elements. This test is important for both HDR and for viewing in a bright room.

We use the same test process for this test as we do for the 2% test, except we display a white rectangle that takes up 25% of the screen.

SDR peak 25% Window

What it is: The maximum luminosity, even if only maintained for a short time, of a white square covering 25% of the screen, with the TV set to be as bright as possible. Measured with local dimming and over SDR signal.
When it matters: Bright rooms; bright objects in SDR video.
Good value: > 400 cd/m2
Noticeable difference: 100 cd/m2

The SDR peak 25% window is done in the same way as the HDR 25%, but instead of measuring the maximum luminance with an HDR signal, it is measured with a standard SDR signal. The SDR peak luminosity of some TVs is sometimes lower than what they can reach with an HDR signal. Since most of the TV content is in SDR, this test is more representative of the level of brightness available while watching standard movies, TV shows, and sports events.

HDR sustained 25% Window

What it is: The lowest maximum luminosity (usually after it has stabilized) of a white square covering 25% of the screen, with the TV set to be as bright as possible. Measured with local dimming and over HDR signal (if supported).
When it matters: Bright rooms; bright objects in HDR video.
Good value: > 1000 cd/m2
Noticeable difference: 100 cd/m2

The sustained 25% window is done in the same way as the peak, but instead of measuring the maximum luminance, we measure the lowest luminance. The peak luminosity of some TVs, like Samsung or Sony, varies in time, so this is the lowest luminosity we measure, without changing anything.

SDR sustained 25% Window

What it is: The lowest maximum luminosity (usually after it has stabilized) of a white square covering 25% of the screen, with the TV set to be as bright as possible. Measured with local dimming and over SDR signal.
When it matters: Bright rooms; bright objects in SDR video.
Good value: > 400 cd/m2
Noticeable difference: 100 cd/m2

The SDR sustained 25% window is done in the same way as the HDR sustained 25%, but instead of measuring the lowest luminance with an HDR signal, it is measured with a standard SDR signal. The peak luminosity of some TVs, like Samsung or Sony, varies in time, so this is the lowest luminosity we measure, without changing anything.

HDR peak 50% window

What it is: The maximum luminosity, even if only maintained for a short time, of a white square covering 50% of the screen, with the TV set to be as bright as possible. Measured with local dimming and over HDR signal (if supported).
When it matters: Bright rooms.
Good value: > 1000 cd/m2
Noticeable difference: 100 cd/m2
50% window test pattern

Our 50% window test measures the maximum brightness of a white rectangle displayed on 50% of the TV’s screen. In real life, this would work out to an image with a very large amount of brightness across the screen – a snowy mountain, a hockey rink, etc.

We consider this to be the most important result to look to get an idea of how well a TV will perform in a bright room. If you watch TV in an area with lots of sunlight or lamps, pay close attention to this result.

We use the same test process for this test as we do for the 2% test, except we display a rectangle covering 50% of the screen.

SDR peak 50% Window

What it is: The maximum luminosity, even if only maintained for a short time, of a white square covering 50% of the screen, with the TV set to be as bright as possible. Measured with local dimming and over SDR signal.
When it matters: Bright rooms.
Good value: > 400 cd/m2
Noticeable difference: 100 cd/m2

The SDR peak 50% window is done in the same way as the HDR 50%, but instead of measuring the maximum luminance with an HDR signal, it is measured with a standard SDR signal. The SDR peak luminosity of some TVs is sometimes lower than what they can reach with an HDR signal. Since most of the TV content is in SDR, this test is more representative of the level of brightness available while watching standard movies, TV shows, and sports events.

HDR sustained 50% Window

What it is: The lowest maximum luminosity (usually after it has stabilized) of a white square covering 50% of the screen, with the TV set to be as bright as possible. Measured with local dimming and over HDR signal (if supported).
When it matters: Bright rooms.
Good value: > 1000 cd/m2
Noticeable difference: 100 cd/m2

The sustained 50% window is done in the same way as the peak, but instead of measuring the maximum luminance, we measure the lowest luminance. The peak luminosity of some TVs, like Samsung or Sony, varies in time, so this is the lowest luminosity we measure, without changing anything.

SDR sustained 50% Window

What it is: The lowest maximum luminosity (usually after it has stabilized) of a white square covering 50% of the screen, with the TV set to be as bright as possible. Measured with local dimming and over SDR signal.
When it matters: Bright rooms.
Good value: > 400 cd/m2
Noticeable difference: 100 cd/m2

The SDR sustained 50% window is done in the same way as the HDR sustained 50%, but instead of measuring the lowest luminance with an HDR signal, it is measured with a standard SDR signal. The peak luminosity of some TVs, like Samsung or Sony, varies in time, so this is the lowest luminosity we measure, without changing anything.

HDR peak 100% window

What it is: The maximum luminosity, even if only maintained for a short time, of a white square covering 100% of the screen, with the TV set to be as bright as possible. Measured with local dimming and over HDR signal (if supported).
When it matters: Bright rooms.
Good value: > 1000 cd/m2
Noticeable difference: 100 cd/m2
100% window test pattern

Our 100% window test measures the maximum brightness of a white rectangle displayed on the entirety of the TV’s screen. Winter sports, advertisements that use a lot of bright colors, and some cartoons, are about the only media you’ll find that approach this level of brightness.

For most people, an image that approaches this level of brightness will be quite rare. For those who do watch video with wide expanses of brightness, though, this will be quite important.

We use the same test process for this test as we do for the 2% test, except we display a white rectangle that takes up the entire screen.

SDR peak 100% Window

What it is: The maximum luminosity, even if only maintained for a short time, of a white square covering 100% of the screen, with the TV set to be as bright as possible. Measured with local dimming and over SDR signal.
When it matters: Bright rooms
Good value: > 400 cd/m2
Noticeable difference: 100 cd/m2

The SDR peak 100% window is done in the same way as the HDR 100%, but instead of measuring the maximum luminance with an HDR signal, it is measured with a standard SDR signal. The SDR peak luminosity of some TVs is sometimes lower than what they can reach with an HDR signal. Since most of the TV content is in SDR, this test is more representative of the level of brightness available while watching standard movies, TV shows, and sports events.

HDR sustained 100% Window

What it is: The lowest maximum luminosity (usually after it has stabilized) of a white square covering 100% of the screen, with the TV set to be as bright as possible. Measured with local dimming and over HDR signal (if supported).
When it matters: Bright rooms.
Good value: > 1000 cd/m2
Noticeable difference: 100 cd/m2

The sustained 100% window is done in the same way as the peak, but instead of measuring the maximum luminance, we measure the lowest luminance. The peak luminosity of some TVs, like Samsung or Sony, varies in time, so this is the lowest luminosity we measure, without changing anything.

SDR sustained 100% Window

What it is: The lowest maximum luminosity (usually after it has stabilized) of a white square covering 100% of the screen, with the TV set to be as bright as possible. Measured with local dimming and over SDR signal.
When it matters: Bright rooms.
Good value: > 400 cd/m2
Noticeable difference: 100 cd/m2

The SDR sustained 100% window is done in the same way as the HDR sustained 100%, but instead of measuring the lowest luminance with an HDR signal, it is measured with a standard SDR signal. The peak luminosity of some TVs, like Samsung or Sony, varies in time, so this is the lowest luminosity we measure, without changing anything.

Additional information

Brightness variance by object size (ABL)

Automatic brightness limiting is a feature that dims the maximum luminance of the TV when a large portion of the TV is displaying a bright color. This is done to help prevent components used in the TV from being damaged when the TV makes the screen really bright across a wide amount of space.

This is a bigger problem with OLED TVs than it is with LED TVs, but it does affect both. Here is a comparison:

  LG EF9500 LG UH8500 Sony X930C
  OLED TV LED TV LED TV w/ highlight brightening  
2%      346.2 cd/m2     302.7 cd/m2    641.7 cd/m2
10%     345.6 cd/m2 312.9 cd/m2 597.1 cd/m2
25%     349.1 cd/m2 311.4 cd/m2 570.2 cd/m2
50%     219.9 cd/m2 311.4 cd/m2 474.3 cd/m2
100%     126.7 cd/m2 314.8 cd/m2 468.5 cd/m2

You can see that with OLED, the brightness is greatly reduced when the screen is displaying large bright areas. With LED, you don’t have much fluctuation unless you enable a highlight brightening feature.

Overall, even for OLED TVs, this isn't a big issue, and you will probably not notice it unless you are actively looking for it.

How to get the best results

For bright rooms

You should set your TV’s lighting to whatever level looks best in your room. Generally, you should keep it a bit dimmer when watching in a dark room and make it very bright in a light room. Note that because brighter lighting brightens lights and darks about equally, the contrast will not be affected by increasing the TV’s luminosity.

For highlight brightening

Some TVs offer different highlight brightening settings, and often these settings require the enabling of local dimming as well. This combination can lead to light blooming off of bright highlights, which is a negative for picture quality.

For that reason, you should choose the highlight setting that gets you the look that you like the best. This may mean getting the brightest highlights of which your TV is capable, or it might mean settling for slightly dimmer highlights that come with less blooming.

For automatic brightness limiting (ABL)

Unfortunately, there is no way to control the ABL. Some TVs dim less than others do, though. If you watch a video with lots of bright space on the screen (hockey, for example, or brightly colored cartoons), you should look for a model that doesn’t have too much of a decrease in brightness between the 25% window test and the larger window tests.

Related settings

  • Backlight/OLED light: Controls the general luminosity of the screen. You should set this to whatever level looks best in your space. On Sony TVs, this setting is called ‘Brightness.’
  • Local dimming: Some TVs also include a setting that can darken the backlight to make blacks extra dark, and sometimes this feature even enables at the same time as the highlight brightening option. It operates on a similar principle to that of highlight brightening, but in reverse. Can be good for dark scenes, but also introduces new issues to picture. Learn more about local dimming
  • Contrast: Changes the brightness of white. Higher settings will result in the peak brightness increasing. It’s almost always okay to set this to the max, and you can do so if you want extra bright highlights. Note that maximum contrast may reduce detail in highlights.
  • Brightness: Does not really control the brightness of the picture, but rather controls the depth of the blacks. Should almost always be left alone. On Sony TVs, this feature is called ‘Black Level.’ We discuss the feature in more detail here.
  • Wide color gamut: In addition to brightening highlights, HDR also relies on the ability to display a wider range of colors than average. Generally, if a TV supports the option to brighten highlights, it will also have the wide color gamut feature. Learn more about wide color gamuts
  • Eco mode/light sensor: Uses a sensor to detect how much light is in the room, and adjusts TV’s lighting accordingly. Can be useful in rooms with changing amounts of light, but disable this if you don’t want the TV’s brightness to change while you are watching.

Other notes

  • Not all TVs that claim to be capable of HDR can brighten highlights. If this is a feature that interests you, be sure to carefully check over a TV’s features before you buy it.
  • The brighter your TV gets, the more power it will consume. If this is a concern for you, you may want to keep your TV’s lighting at a lower level.

Conclusion

A TV’s peak brightness indicates how bright images can get on the TV. It matters a lot for people who watch TV in a bright room, and for people who want HDR media to have really bright highlights. To find out the TV’s peak brightness in multiple situations, we display a series of white rectangles of varying size on each TV that we test, measuring the luminance of each window.

To get the best results, you should choose a level of luminosity that looks good in your space. For HDR, you should also enable the highlight brightening feature. Note that OLED TVs will dim their luminosity when displaying mostly bright images. If you watch lots of bright videos (like hockey), you should either choose an OLED model that dims less, or get a LED TV instead. If you get a TV with good peak brightness for your space and media, you’ll be able to enjoy very bright video whenever you want it.

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Questions & Answers

2 ANSWERED QUESTIONS
10
Hey guys, your website is incredible! Are you planning to also review the new LG 86UH9500? I'm currently eyeing to purchase that TV but given its price I'd love to hear your guys' take on it first. Looking forward to hearing from you!
We will review the UH9500, but not soon. Only at the end of summer/fall. Also, we will buy the 65", not the 86".
1
Have you guys recalibrated your Vizio P Series since the firmware update?
The peak brightness was re-measured and updated after the 1.1.14.4 firmware, however the calibration was performed on the 1.1.6.12 firmware.
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