Backlight Bleed Test
Test your screen for backlight bleed and uneven light around the edges and corners using fullscreen dark backgrounds.
Preview · press Start for true full screen
Starting from: Black
For the most useful result, test at your normal display brightness and viewing position.
Keys: ← / → switch · F full screen · Esc exit
Test backgrounds
#000000Double-click any background to jump straight into full screen.
Guide
How to test
01
Dim the room
Lower ambient light so faint leaks are visible.
02
Set normal brightness
Use your usual brightness and picture mode.
03
Show black screen
Go full screen to display the black test field.
04
Check edges and corners
Look around edges and corners for unwanted light.
Guide
How to inspect your screen
Look at
- Four corners
- Left and right edges
- Top and bottom edges
- Areas around the bezel
Look for
- Bright patches
- Light leaking from an edge
- Uneven corner brightness
- Large cloudy areas
Know the difference
Backlight Bleed vs IPS Glow
Backlight Bleed
Backlight bleed is generally seen as localized light leakage, often around the edges or corners of the display.
IPS Glow
IPS glow can appear as a broader glow that changes with viewing angle.
This tool cannot automatically determine which one you are seeing. It provides a controlled visual test so you can inspect the display yourself.
Terminology
Bleed-related terms
Backlight Bleeding
Physical light leakage from edges or corners. Its position stays fixed and does not change with viewing angle.
IPS Glow
A broad, often silvery glow on IPS panels. It is a viewing-angle-dependent characteristic of many IPS displays and is not necessarily a panel defect.
Clouding / Mura
Patchy brightness unevenness on dark backgrounds, often in the middle of the screen rather than at the edges.
Flashlighting
Cone-shaped beams of light emanating from the corners, a specific and common form of backlight bleed.
Learn
What is backlight bleed?
Backlight bleed is visible light escaping around areas of an LCD display where the backlight should appear more uniform. It is commonly noticeable near edges and corners when viewing dark content.
How to test for backlight bleed
- Set the display to normal viewing brightness.
- Darken the surrounding room if practical.
- Start the fullscreen black test.
- Look at each corner and edge.
- Repeat with near-black backgrounds.
- Decide whether the visible light is significant during normal use.
Is backlight bleed normal?
Some variation can occur with LCD displays, particularly around edges and corners. How significant it looks depends on the display and the viewing conditions.
Panel types
Bleed tendencies by panel type
IPS
May show IPS glow (angle-dependent) as well as some corner bleed. Wide viewing angles and generally accurate colors.
VA
High native contrast usually gives strong dark scenes, but larger VA panels may show clouding or brightness unevenness.
TN
Less prone to visible bleed, but narrow viewing angles and color shift limit how reliably you can judge dark uniformity.
OLED
No backlight, so backlight bleed is not possible. Unevenness on OLED has different causes. This test is designed for LCD displays.
Practical steps
How to make backlight bleed less noticeable
Lower brightness
Reducing brightness for everyday use can make mild bleed far less noticeable.
Use bias lighting
A soft light behind the display can reduce how prominent dark-room bleed appears.
Sit centered
Sitting centered and at eye level helps separate angle-dependent glow from fixed leakage.
Compare at normal viewing conditions
Test at normal brightness and in your normal viewing conditions before deciding whether the issue matters.
What is Backlight Bleed Test?
A backlight test shows dark screens. It helps you see if light leaks around the edges or corners. You look at the dark test in a dim room with normal brightness.
FAQ
Backlight Bleed Test FAQ
01How do I test my monitor for backlight bleed?
Display a full black screen in a dim room and look around the edges and corners for unwanted light.
02What does backlight bleed look like?
It usually appears as bright or grayish patches around the edges or corners of an otherwise dark screen.
03Is some backlight bleed normal?
A small amount can be visible on some LCD displays. What you see can also depend on the room lighting, viewing angle, and display settings.
04What is the difference between backlight bleed and IPS glow?
Backlight bleed is usually caused by light leaking through the panel edges. IPS glow is a viewing-angle-dependent glow commonly seen on IPS displays.
05Can OLED screens have backlight bleed?
OLED displays do not use a backlight, so traditional backlight bleed does not apply to them.
06Why does backlight bleed look worse in a dark room?
The surrounding screen is darker, making small amounts of unwanted light easier to see.