Our TV Picture Quality Tests
SDR Peak Brightness
- 27.9% Real Scene Peak Brightness
- 2.0% Peak 2% Window
- 2.0% Peak 10% Window
- 2.0% Peak 25% Window
- 2.0% Peak 50% Window
- 2.0% Peak 100% Window
- 1.0% Sustained 2% Window
- 1.0% Sustained 10% Window
- 1.0% Sustained 25% Window
- 1.0% Sustained 50% Window
- 1.0% Sustained 100% Window
- 0.5% Automatic Brightness Limiting (ABL)
Brightness refers to a TV's maximum luminance. A higher brightness means the TV can make the picture look brighter, which can help with visibility in a bright room.
For these tests, we take measurements of the brightness of a few white rectangles in SDR, each covering different sizes on the screen. The measurements are in cd/m², also known as 'nits.'
Test results
When It Matters
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 can be difficult, or even impossible, to see the screen properly. If you want to place your TV in a well-lit room, it's also important to get a TV with good reflection handling.
- Watching HDR video. There are several HDR formats that allow for brighter and more vivid colors, so even if a TV supports one of these formats, it's even more important to get a bright TV for a true HDR experience. This allows highlights to pop the way they're supposed to. We don't test HDR peak brightness the same way we measure SDR peak brightness, though. Learn more about our HDR Peak Brightness Tests.
If your daily use applies to either of those situations, it's important to get a TV that has high brightness. As you can see in the pictures below, these are two TVs with excellent reflection handling but different brightness. A TV with high brightness results in a more vivid image that's easier to see than one with low brightness.
Hisense H9G: High brightness and excellent reflection handling
Our Tests
Our testing for SDR brightness is fairly straightforward. We use our calibrated settings for the TV while setting the backlight/brightness setting to max and using the recommended local dimming setting. We use a Konica Minolta LS-100 Luminance Meter to measure the brightness with different content.
We use a video and five test pictures to measure the brightness in SDR. The real scene video is supposed to represent content in most shows or movies with bright scenes. Also, the test windows, especially the smaller ones, are meant to test for small highlights.
2% Window Test Pattern
10% Window Test Pattern
25% Window Test Pattern
50% Window Test Pattern
100% Window Test PatternSDR Real Scene Brightness
The SDR Real Scene Peak Brightness test is most representative of real-world use. Before playing the video, we 'warm up' the TV so that the pixels aren't 'cold' for this test; almost like an athlete stretching their muscles before physical activity, it's important to get the pixels going before the test. We use the luminance meter and focus on the lamp in the upper-left side of the video for 30 seconds to get our final measurement. Anything above 365 cd/m² should be good enough to combat glare in well-lit rooms. Also, the final luminance measurement can vary up to 20 cd/m² between measurements.
SDR Peak Window
Our peak window tests measure the maximum brightness of a white rectangle displayed on an area covering a certain percentage of the TV’s screen. This provides an idea of how bright a small highlight—the sun, a distant explosion, etc.—might look on-screen, but the larger areas can also represent very bright areas, like if you're watching something with a bright sky.
We use the same setup as the real scene test and measure the brightness immediately after the white square appears on-screen. This is because the TV is the brightest at this point. We repeat the test with the five white slides shown above, each representing different types of content.
SDR Sustained Window
We measure the SDR sustained window with the same test images as the SDR peak window, but the only difference is that we test for brightness after the window has been displayed for a few seconds. This allows the TV to 'stabilize' its brightness and is more representative of content with bright areas that stay on for an extended period, like on a hockey broadcast. Luckily, many TVs don't get much dimmer when a highlight stays on the screen longer.
Automatic Brightness Limiter
TVs use algorithms to limit how bright the screen gets, especially with large areas, like in our 100% peak window test. It's done to prevent the entire screen from getting too bright and damaging internal electronics. What this essentially means is small areas get brighter than large areas, and we want to know just how much difference there is between the two. Our Automatic Brightness Limiter (ABL) coefficient variant calculates the difference in brightness between the sustained windows tests after normalizing for noticeable differences with the Perceptual Quantizer (PQ) EOTF. This means we only calculate the noticeable differences that we can see when watching TV.
A TV with an ABL of 0 means that the brightness doesn't change across different content. A high ABL is usually found on OLEDs, as large areas are noticeably less bright on those TVs. Also, it's possible for small highlights to be less bright than larger areas because of frame dimming on some TVs, as seen on the Vizio M7 Series Quantum 2020; in this case, the ABL is also high. ABL isn't something you should worry about too much if you just watch SDR content, as most TVs can maintain a high brightness level in SDR without any ABL.
Unfortunately, there's no way to control the ABL. Some TVs dim less than others do, though. If you watch content with large areas of bright colors, like hockey 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 100% window test. Some TVs allow you to disable ABL from the service menu, but we don't recommend doing this, as ABL is designed as a protection mechanism for the TV. Disabling ABL could cause your TV to overheat.
Additional Information
Linearizing Luminosity
For the ABL calculation to be significant, it should correspond to the way we perceive different luminosity levels. The eye is much more sensitive to small changes in luminosity in a dark environment than in a bright one. Although the measured change in luminosity may be the same, the brighter source is better because we don't notice the change in brightness as much. Essentially, if a screen goes from 25cd/m² to 20 cd/m², it's more noticeable than a screen going from 100 cd/m² to 95 cd/m². This linearization is done with the PQ EOTF, as you can see below.
Each step of 1/4096 along the PQ curve shows the nonlinear relationship between the target luminosity (vertical axis), and a similar, just noticeable difference in the stimulus (horizontal axis)
PQ is a function that relates luminosity with noticeable differences in brightness. When the PQ curve is divided into 4096 segments (12-bit), there are smaller steps that relate to the change in brightness; the horizontal dotted lines represent each step, and as you can see, the first step in each segment represents a higher change than the last segment. We use this to linearize all of our luminosity measurements for this test, ensuring the ABL best represents what's seen.
How To Get The Best Results
bright rooms
You should set your TV’s backlighting/brightness 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 room with lots of light. Adjusting the luminance of the TV doesn't affect picture quality, so you can easily put it to whatever setting you like.
Recommended Settings
- Backlight/Brightness/OLED Light: These settings are what increase the luminosity. The majority of LED TVs call it Backlight, but Samsung and Sony use Brightness. On OLEDs, it's usually called OLED Light, but the Vizio OLED 2020 has a Luminance setting. Whatever they're called, these settings are meant to adjust the luminance and are the best setting to use to get the brightest image possible.
- Local Dimming: Some LED TVs include a feature that darkens the backlight to make blacks extra dark, and sometimes this feature even makes highlights even brighter. Local dimming isn't always perfect, as it could cause blooming around bright objects. Learn more about local dimming
- Contrast: The contrast setting increases the brightest white, which could help increase the overall luminosity. However, changing this setting also affects picture quality, so we don't recommend changing it for the most part.
- Brightness: Opposite of contrast, the brightness setting controls the black level, and on some TVs, the setting itself is called 'Black Level'. Decreasing it makes blacks darker, but that means you can easily lose details, so we don't recommend changing it.
- Gamma: Gamma affects the brightness of the overall scene, but it doesn't have an impact on the luminosity. In our testing, we want TVs to follow a gamma target of 2.2; anything higher results in a darker overall image and lower means the image is brighter. Some TVs have gamma settings, so you should change it to your liking if you notice the overall image is too dark, even if you have the backlight at its max.
- Eco Mode/Light sensor: Some TVs use a sensor to detect how much light is in the room and adjust the backlight accordingly. It can be helpful, but it can also change the brightness often while you're watching, so it's best to turn it off.
At the end of the day, you're the one watching TV, so if you want to make the image brighter, do whatever it takes to make it look better for your viewing experience. These are just generalized recommendation settings, and it changes between TVs.
Conclusion
A TV's brightness indicates how bright images can get on the screen. It matters most if you watch TV in a well-lit room, as you want your screen to get bright enough to combat glare; otherwise, it may be hard to see. We test for a TV's brightness to know exactly how bright it can get, but also to see if it remains a consistent brightness level across different content. If you watch TV in dark rooms, then brightness shouldn't be something to worry about.