Backlight Bleed Test 🖥️ Free Backlight Bleed Check

Backlight bleed is a common issue with LCD screens where unwanted light leaks around the edges or corners of the display. This creates bright spots or patches, especially noticeable on dark backgrounds. BacklightBleedTest.org provides you with the simplest way to check if your monitor, TV, or laptop suffers from backlight bleed. Testing is completely free! Follow these steps to run the test:

1. Clean your screen 🧽

Make sure your display is clean and free of dust or smudges. Dirt can sometimes look like uneven lighting and lead to confusion during the test.

2. Launch our backlight bleed test 🚀

Our backlight bleed test will open in a new window and display solid colors, especially black. Switch to full screen mode to ensure the test covers your entire display.

3. Inspect your screen carefully around the edges 🕵🏻

When your screen is showing black, check the corners and edges of your display. If you see glowing spots or irregular bright areas, your screen might have backlight bleed.

Backlight Bleed Test

What is backlight bleed?

Backlight bleed is a side effect of how LCD screens are built. Unlike OLED, which lights each pixel individually, LCD panels need a backlight (usually LEDs) that shines through several layers to create the image you see. If the backlight isn’t perfectly contained, some light can escape around the edges or corners of the display.

Backlight bleed usually looks like:

  • Glowing corners or edges on a dark screen
  • Uneven lighting patches visible during movies, games, or dark backgrounds
  • A bright haze in low-light scenes

For more information, check out our article on what black light bleed is.

An example of a screen with backlight bleed on the edges

📷 Example of backlight bleed on an LCD screen

What causes backlight bleed?

Backlight bleed is due to the backlight panel at the back of your LCD screen being misaligned with the colouring panel (the liquid crystals). The most common causes of backlight bleed are: 

  • Panel assembly tolerances – Tiny gaps or imperfections when the layers of the screen are put together can allow light to leak through.
  • Uneven pressure – If the frame or bezel presses too tightly or unevenly on the panel, the liquid crystals don’t block the light evenly, leading to brighter spots.
  • Panel aging – Over time, materials inside the screen may warp slightly, making backlight bleed more visible.
  • Lower build quality – Cheaper LCD panels often have less precise construction, which increases the chances of light leakage.

Is backlight bleed normal?

A small amount of backlight bleed is common in LCD screens because they use a backlight behind the panel. Some of that light can leak around the edges, which is usually not a defect but a normal characteristic of LCD technology. However, if the bleed is very strong, it can be distracting, especially when watching movies or playing games in dark environments.

By contrast, OLED screens do not suffer from backlight bleed at all. This is because each pixel in an OLED display produces its own light and can turn completely off, giving you perfect blacks without any glow around the edges.

Can backlight bleed be fixed?

If your screen has noticeable backlight bleed, here are a few things to consider:

  1. 📝 Check your warranty - Some manufacturers consider heavy backlight bleed a defect. If your display is new or still under warranty, you may be eligible for a replacement. Always check your warranty terms and contact customer support if the bleed is severe.
  2. 💡 Adjust the brightness - Reducing your screen’s brightness can make the bleed far less noticeable, especially in dark rooms. Most people only notice backlight bleed at very high brightness levels.
  3. 🔄 Screen positioning - The bleed may look worse depending on your viewing angle. Slightly tilting or repositioning your monitor can reduce how visible the glow appears.
  4. 🔧 Panel replacement - In some cases, the only real fix is to replace the panel itself. This is usually done under warranty or by a professional repair service, since backlight bleed cannot be corrected with software or simple adjustments.

Check our or other screen tests

BacklightBleedTest.org and its affiliate websites offer you other screen tests to make sure your display works well. You may find them below.

Dead Pixel Test

DeadPixelTest.org helps you check your screen for any dead, bad, or stuck pixels that might impede your media, work, or gaming experience. By running this test, you can make sure that your monitor is flawless and has no odd dots that can reveal annoying. You will be able to display colours on the full width of your screen in order to check for any dead pixels or stuck pixels. DeadPixelTest.org also provides a dead pixel fixer that might help you revive your bad pixels.

Dead Pixel TestDead Pixel Fix

Frame Rate and Motion Blur Test

FrameRateTest.org helps you see your screen's refresh rate, which is how many times per second the image is updated. A higher refresh rate, like 120Hz or more, makes motion look much smoother, which is great for gaming and watching videos. This test also checks for motion blur, which is when moving objects on your screen look blurry. By running this test, you can make sure your display is performing as it should for a clear and smooth picture.

Test your Frame Rate

Screen Resolution Test

DeadPixelTest.org's screen resolution test is a simple tool to find out the resolution of your screen. Your screen's resolution is the number of pixels it can show, like 1920x1080 (Full HD) or 3840x2160 (4K). Knowing your resolution is important for getting the best picture quality and making sure your computer or other devices are set up correctly. This test instantly tells you your screen's native resolution and many other useful information about your display.

Test your Screen Resolution

Screen Contrast Test

You can use DeadPixelTest.org's screen contrast test to see how well your screen shows the difference between black and white. Good contrast means you can see all the details in both very dark and very bright parts of an image at the same time. This test shows a pattern of black and white gradients to help you adjust your screen's contrast settings for the best possible image quality, so you don't miss any details.

Test your Screen Contrast