Screen Display & Color Test
Professional Dead Pixel & Backlight Bleed Checker
Cycle through pure solid colors (White, Black, Red, Green, Blue) to detect dead pixels, stuck pixels, backlight bleeding, and color uniformity issues on any screen.
How to Test Your Screen for Defects
This professional-grade display test uses pure solid colors to reveal screen imperfections that are invisible during normal use. Works on monitors, laptops, phones, tablets, and TVs.
- Enter Fullscreen: Click 'Start Test' to display the first color (white) across your entire screen. Fullscreen mode eliminates UI distractions.
- Cycle Through Colors: Tap or click to switch between White → Black → Red → Green → Blue. Each color reveals different types of defects.
- Inspect Each Color Carefully: On white/colored screens, look for black dots (dead pixels). On black screens, look for colored dots (stuck pixels) and light leaking from edges (backlight bleeding).
- Dim the Room: For best results testing backlight bleeding and black uniformity, run the test in a dark room. IPS glow and bleeding are most visible in low light.
Types of Screen Defects
Pixels that receive no power and remain black regardless of the displayed content. Dead pixels are most visible on white or bright-colored backgrounds. They cannot be fixed by software , only screen replacement can address true dead pixels.
Pixels stuck displaying one color (red, green, or blue) at all times. Unlike dead pixels, stuck pixels can sometimes be fixed using our Pixel Fixer tool. They're most visible on black backgrounds.
Light leaking from the edges or corners of LCD screens, appearing as bright patches on black backgrounds. More common on IPS panels. Minor bleeding is normal; severe cases may warrant replacement.
A white/silver glow from the corners of IPS displays when viewed at angles. Unlike backlight bleeding, IPS glow shifts position as you move your head. It's a panel characteristic, not a defect.
Uneven brightness across the screen, appearing as darker or brighter patches. Most visible on gray or low-brightness backgrounds. Often caused by manufacturing inconsistencies.
When to Run a Screen Display Test
Regular screen testing helps catch defects early. Here are the most important times to check your display:
- Before Purchase: Always test new monitors, laptops, phones, or TVs before the return window closes. Even brand-new screens can have dead pixels.
- After Repairs: Verify screen quality after any repair or replacement. Third-party screens may have more defects than OEM.
- Buying Used Devices: Run this test before completing any used device purchase. Sellers may not disclose (or notice) pixel defects.
- Warranty Claims: Document defects with photos/video of this test running. Most manufacturers have dead pixel policies (often 3-5+ required for warranty).
- Periodic Checkups: Run the test every few months. Pixels can fail over time, and early detection helps with warranty claims.
What Each Color Reveals
Different test colors expose different types of screen problems:
White Background
Best for finding dead pixels (appear as tiny black dots). Also reveals dust particles trapped under the screen and color tinting issues.
Black Background
Essential for detecting stuck pixels (colored dots), backlight bleeding (light edges), IPS glow, and overall black uniformity.
Red Background
Reveals green or blue stuck sub-pixels. Also good for checking red color accuracy and uniformity across the panel.
Green Background
Reveals red or blue stuck sub-pixels. Green is the brightest color channel, so dead pixels are very visible here.
Blue Background
Reveals red or green stuck sub-pixels. Also useful for checking blue color accuracy, which is often weaker on budget panels.
Screen Testing FAQ
How many dead pixels are acceptable?
That depends on your standards and the manufacturer's policy. Premium displays should have zero dead pixels. Budget monitors may allow 1-3. Most manufacturers won't replace a screen for a single dead pixel , check warranty terms before purchase.
Can dead pixels spread?
Dead pixels themselves don't spread, but whatever caused one dead pixel (physical damage, manufacturing defect) may cause more over time. Monitor new defects and document them for potential warranty claims.
Why test on a black background specifically?
Black backgrounds reveal the most defects: stuck pixels light up brightly, backlight bleeding becomes visible, and you can assess true black levels. It's the most critical test for image quality.
Should I test in a dark room?
Yes, for backlight bleeding and black uniformity tests. Ambient light masks screen defects. Test in darkness using the black background to see true panel performance.
What's the difference between dead and stuck pixels?
Dead pixels don't light up at all (black on any background). Stuck pixels are 'on' permanently in one color (visible as colored dots on black). Stuck pixels can sometimes be fixed; dead pixels usually cannot.