Backlight Bleed Test

Check your monitor for backlight bleed and IPS glow with a pure black full-screen panel. Free, instant, and runs entirely in your browser.

Written by J. Hassan, Display Technology Specialist · Last updated: May 2026

💡 Key Takeaway: Backlight bleed is light leaking from the edges of a monitor. IPS glow is a shifting haze visible when viewing an IPS panel from an angle. To test for both, turn off your room lights, set monitor brightness to 100%, and display a pure black full-screen image.

Frequently Asked Questions

What is a dead pixel? ▼

A dead pixel is a pixel on your screen that no longer lights up. It appears as a permanent black dot regardless of what content is displayed. Dead pixels are caused by manufacturing defects or physical damage to the display panel.

How do I test for dead pixels? ▼

Click each color button above to fill your screen with a solid color. Look carefully for any dots that don't match the displayed color. Dead pixels appear black on any background, while stuck pixels show a fixed color that's only visible on contrasting backgrounds.

Can dead pixels be fixed? ▼

Dead pixels (completely black) usually cannot be fixed as they indicate a hardware failure. Stuck pixels (showing a fixed color) can sometimes be unstuck by running pixel-cycling patterns for several hours or by applying gentle, targeted pressure with a soft cloth. If your monitor is under warranty, contact the manufacturer — most have a dead pixel policy.

How many dead pixels are acceptable? ▼

This depends on the manufacturer's policy. The ISO 13406-2 standard defines tolerance classes. Most premium monitors allow zero dead pixels for replacement, while budget displays may allow 3-5 before a warranty claim is accepted. Check your specific manufacturer's dead pixel policy.

Does this test work on all screens? ▼

Yes. This test works on any screen that can display a web browser — monitors, laptops, tablets, phones, and even TVs with a built-in browser. For best results, use fullscreen mode and test at native resolution.

How to Fix a Stuck Pixel

Unlike dead pixels, stuck pixels are often fixable because the sub-pixel transistor is still powered — it's just locked in one state. There are two established techniques:

Darken the room — Turn off all lights and close the blinds. Backlight bleed is almost impossible to see in a well-lit room.
Maximize brightness — Use your monitor's hardware buttons (OSD) to turn the brightness setting all the way up to 100%.
Start the test — Click the "Start" button above to enter a full-screen, pure black environment.
Examine the edges — Look carefully around the bezel (the plastic frame) of your monitor. If you see yellow or white clouds of light leaking in from the edges, you have backlight bleed.
Shift your head — Move your head left, right, up, and down. If the glowing spots move or change intensity as your viewing angle changes, you are experiencing IPS glow, not backlight bleed.

What is Backlight Bleed?

Backlight bleeding occurs when the light source (the backlight) inside an LCD monitor is not fully blocked by the display panel and leaks out around the edges. It typically looks like cloudy, uneven patches of light seeping in from the corners or sides of a purely black screen.

This is an extremely common issue caused by manufacturing tolerances. The bezel might be pinching the display panel too tightly in some spots, or the internal layers of the LCD may not be perfectly aligned. Because it is a physical, hardware-level issue, it cannot be fixed with software.

Backlight Bleed vs. IPS Glow

If you own an IPS (In-Plane Switching) monitor, you will inevitably encounter "IPS Glow." While it looks similar to backlight bleed, it is a completely different phenomenon.

Visible from any angle. It is light literally leaking out from the edges of the frame due to physical pressure or assembly defects. It is usually yellow or bright white and is stationary.

Only visible from an angle. It is a natural characteristic of IPS technology. As you move your head, the "glowing" corners will shift or disappear. It often has a slight blue or golden tint.

Is Backlight Bleed Normal? (When to Return Your Monitor)

A minor amount of backlight bleed is considered "normal" by almost every LCD monitor manufacturer. Because perfection is nearly impossible in mass production, slight glowing in the corners is expected, especially on budget displays.

You should consider returning/RMAing your monitor if:

The bleeding is visible in a normally lit room (not just in pitch black).
It distracts you while playing games or watching movies with dark scenes (like letterbox bars).
There is a distinct, sharp "flashlight" beam of light shooting from the bezel, rather than a soft cloud.

Can You Fix Backlight Bleed?

Because backlight bleed is a hardware assembly issue, there is no software fix. However, there are ways to mitigate it:

Lower your brightness: Nobody should use a monitor at 100% brightness in a dark room. Lowering the brightness to a comfortable 30-50% will drastically reduce the visibility of the bleed.
Add ambient lighting: Turning on a desk lamp or installing an LED bias light strip behind your monitor tricks your eyes into perceiving deeper blacks, making the bleed far less noticeable.
The "Massage" technique (Use with extreme caution): Some users report that gently massaging the affected area of the screen with a microfiber cloth can relieve the physical pressure causing the light leak. Warning: Applying too much pressure can permanently break the liquid crystals or cause dead pixels.

Why OLED Monitors Don't Have Backlight Bleed

If you absolutely cannot stand backlight bleed or IPS glow, your only permanent solution is to upgrade to an OLED (Organic Light-Emitting Diode) display. Unlike LCD, IPS, TN, or VA panels, OLED displays do not use a backlight. Every single pixel on an OLED screen produces its own light. When an OLED pixel needs to display black, it simply turns completely off. This results in infinite contrast ratios, perfect blacks, and zero possibility of backlight bleed or glow.

Frequently Asked Questions

Does backlight bleed get worse over time? ▼

Generally, no. Backlight bleed is a physical characteristic of how the panel was assembled. While it might fluctuate very slightly due to temperature changes expanding and contracting the plastic bezel, it will not progressively worsen over months or years.

Do VA panels have backlight bleed? ▼

Yes. While VA (Vertical Alignment) panels have much better native contrast ratios and deeper blacks than IPS panels (making bleed less noticeable), they still rely on a backlight and a physical bezel. Therefore, they can still suffer from backlight bleeding and "clouding," though they do not suffer from IPS glow.

Is it bad to run my monitor at 100% brightness? ▼

It will not damage the monitor, but it will consume more power and generate more heat. More importantly, using 100% brightness in a dimly lit room causes severe eye strain. High brightness should only be used in very well-lit environments or when consuming HDR content.

Reference: Wikipedia — Defective pixel | ISO 13406-2 Pixel Defect Standard

Sources & References: Wikipedia: Defective Pixel · Wikipedia: ISO 13406-2 Pixel Defect Standard