How to use the pixel test
Open the test on the screen you want to inspect. Use fullscreen mode so browser bars, cursors, notifications, and app controls do not hide or imitate a small defect.
Clean the glass or panel first
Dust, oils, protector debris, and small surface marks can look like bad pixels until they move or wipe away.
Raise brightness enough to see small dots clearly
Use a brightness level that makes tiny dark or bright points visible without washing out the screen.
Turn off color-shifting settings if possible
Night mode, color filters, adaptive color, True Tone-style settings, and auto brightness can change how solid test colors appear.
Check black, white, red, green, and blue screens
Each color reveals a different kind of pixel or subpixel behavior.
Scan the center, edges, and corners slowly
Move by sections instead of clicking through colors quickly.
Recheck the exact same point
A repeatable point matters more than one quick glance.
Take a photo if the same mark repeats
Capture the relevant test color and one normal-use view if you may need return, warranty, resale, or trade-in proof.
What each color screen helps reveal
| Test screen | What it helps reveal | What to check |
|---|---|---|
| Black | Bright, hot, or stuck-on pixels; edge glow; backlight bleed. | Look for single bright dots versus wider glow or haze. |
| White | Dark or dead pixels, dust, pressure marks, and cloudy patches. | Look for fixed black dots that do not wipe away. |
| Red | Red subpixel behavior and color-specific defects. | A black or wrong-colored point may suggest a subpixel issue. |
| Green | Green subpixel behavior and color-specific defects. | Compare the same point against red and blue. |
| Blue | Blue subpixel behavior and color-specific defects. | Blue-only problems can point to a subpixel issue. |
What the pixel test can show
A browser pixel test can help reveal visible display issues by showing solid color and contrast backgrounds. It can help you spot repeatable dead pixels, stuck pixels, hot or bright pixels, dark subpixel defects, color-specific subpixel behavior, dust look-alikes, burn-in-like shapes, pressure marks, lines, and backlight or uniformity issues.
The test is strongest when the same point behaves the same way across repeat checks.
What the pixel test cannot confirm
A browser test cannot prove the exact hardware cause of a defect. It cannot decide warranty eligibility, confirm manufacturer policy coverage, inspect internal electronics, or guarantee repairability.
It also cannot repair dead pixels. Use the result as evidence for the next step, not as a final manufacturer diagnosis.
What your screen issue may be
| What you see | What it may be | Best test screen | What to do next |
|---|---|---|---|
| Tiny black dot on white screen | Dead pixel, dark subpixel, dust, or protector debris. | White, then red, green, and blue. | Clean and retest; document if the same point remains. |
| Tiny red, green, or blue dot on black or white | Stuck pixel or bright subpixel. | Black plus red, green, and blue. | Recheck the location; if repeatable, use the stuck-pixel handoff. |
| Bright white dot on black | Hot/bright pixel or stuck-on pixel. | Black. | Compare against red, green, and blue; document if it stays bright. |
| Colored dot visible only on one color | Subpixel issue or rendering artifact. | The matching red, green, or blue screen. | Retest in fullscreen and another browser or app. |
| Cloudy patch or pressure spot | Pressure mark, panel damage, or internal layer issue. | White, gray if available, and normal content. | Do not treat it as one pixel; document the shape and size. |
| Thin vertical or horizontal line | Panel, cable, driver, or display path issue. | Any solid color. | Test another input or app; seek device support if persistent. |
| Faint ghost image from previous content | Image retention or burn-in. | White, gray, and normal content. | Run the burn-in test; do not classify it as one pixel. |
| Uneven glow near edges or corners | Backlight bleed, IPS glow, or uniformity issue. | Black in a dim room. | Use the backlight bleed test. |
| Dust or mark that moves when cleaned | Surface debris. | White or another bright color. | Clean the panel; no pixel claim needed. |
| Issue visible only in one app or browser | App, browser, scaling, cable, GPU, or video-path issue. | The same color in another context. | Retest outside that app before documenting a panel defect. |
Dead pixel, stuck pixel, hot pixel, or screen damage?
| Type | What it looks like | Can software usually help? | Best next step |
|---|---|---|---|
| Dead pixel | Tiny black point that does not light correctly; easiest to see on white or bright RGB screens. | Usually no. | Document it and check return or warranty options. |
| Stuck pixel | Fixed red, green, blue, cyan, magenta, yellow, or white point; easiest to see on black or contrasting colors. | Sometimes. | Try the stuck pixel fixer. |
| Hot/bright pixel | Bright white or nearly white point; easiest to see on black. | Sometimes, if it behaves like a stuck-on pixel. | Try a controlled stuck-pixel attempt, then document if unchanged. |
| Subpixel issue | Dot appears wrong only on certain red, green, or blue screens. | Sometimes if stuck; no if the subpixel is dead or off. | Retest on RGB and document the color behavior. |
| Burn-in or image retention | Ghosted logo, keyboard, status bar, or interface shape. | Not with a stuck-pixel fixer. | Use the burn-in test. |
| Pressure mark or physical damage | Cloudy patch, bruise, bright spot, lines, or distortion. | No. | Document the damage pattern and support path. |
| Backlight bleed or uniformity issue | Glow, haze, or bright area near an edge or corner. | No. | Use the backlight bleed test. |
When to try the stuck pixel fixer
Use the pixel test first. If the same point stays colored or bright while the rest of the screen changes, it may be a stuck or hot pixel. In that case, try the stuck pixel fixer as the next step.
Do not expect a fixer to repair a black dead pixel, cracked screen, pressure mark, burn-in, backlight bleed, cloudy patch, or display line. Those patterns need documentation, support, repair, return, or another diagnostic route instead.
When flashing colors will not help
Flashing colors are the wrong next step when the mark stays black, looks like a cloudy pressure patch, forms a line, follows an old logo or status bar, or spreads as corner glow. For a ghosted image, run the burn-in test. For edge glow or haze, use the backlight bleed test. For pressure damage or cracked, bruised, or distorted areas, document the issue for warranty or support before deciding whether to repair or replace the screen.
Save proof before return, warranty, resale, or trade-in
If the same point repeats, save proof before changing settings, starting a repair attempt, or sending the device for service. Manufacturer policies can vary by product line, region, warranty, defect count, defect location, and panel type.
Photograph the relevant patterns
For a dark defect, include white plus at least one color screen. For a bright defect, include black or another dark screen.
Capture close-up and normal-use context
A close dot photo is stronger when paired with a normal viewing photo that shows how the issue appears during use.
Record model, serial number, purchase date, and seller
Return and warranty workflows often depend on timing, region, seller, and product line.
Label the behavior, not just the annoyance
Write down whether the point stayed black, stayed one color, stayed bright, or only appeared in one app or browser.
Check the retailer return window first
A retailer return or exchange is often simpler than a manufacturer warranty claim after the return period closes.
Sources checked
We checked official display, device, and manufacturer support pages to keep the testing notes aligned with current public guidance.
- Dell Display Pixel Guidelines · Dell SupportChecked June 3, 2026: Bright/dark subpixels, RGB pattern guidance, and model-dependent policy thresholds.
- HP Notebook PCs and Tablets - Learning about LCD and OLED panel defects and terminology · HP SupportChecked June 3, 2026: LCD/OLED terminology, always-on/off dots, lines, spots, and related display conditions.
- LCD Display Pixel Policy - Idea/Lenovo Laptops and Tablets · Lenovo SupportChecked June 3, 2026: Pixel policy thresholds and product-class variation.
- Acer Dead Pixel Policy · Acer SupportChecked June 3, 2026: Bright and dark subpixel definitions and regional warranty thresholds.
- ASUS LCD Monitor Bright/Dark Dot Warranty Table · ASUS SupportChecked June 3, 2026: Bright/dark dot warranty terms and product variation.
- TV - Pixel Outage or Colored Dots on Screen · LG SupportChecked June 3, 2026: Pixel outage and colored-dot support context for TVs and displays.
- Surface repair tool · Microsoft LearnChecked June 3, 2026: Surface display diagnostics and repair-validation workflow context.
- ISO 9241-307:2008 display compliance test methods · ISOChecked June 3, 2026: Standards-family reference for electronic visual display analysis and compliance methods.
Pixel Test FAQ
What is a pixel test?
A pixel test shows solid screen colors so you can inspect the display for points that do not change correctly. It is useful for finding dead pixels, stuck pixels, hot pixels, subpixel issues, and some look-alikes such as dust, burn-in, or backlight bleed.
What color is best for finding dead pixels?
White and bright color screens are usually best for finding dark or dead pixels. A black dot that remains in the same place on white, red, green, and blue screens is stronger evidence than a dot seen once.
How do I tell if a pixel is dead or stuck?
A dead pixel usually looks black because it is not lighting correctly. A stuck pixel still emits light and often stays red, green, blue, cyan, magenta, yellow, or white while nearby pixels change.
Can a dead pixel be fixed?
A true black dead pixel usually cannot be fixed with browser software. If it repeats on bright test screens, document it and check the retailer return window, warranty terms, or device support options.
Can a stuck pixel be fixed?
Sometimes. A stuck pixel still emits light, so a controlled color-cycling tool may be worth trying. Results are not guaranteed, and a stuck-pixel fixer should not be used as a repair path for black dead pixels or physical damage.
Should I use the stuck pixel fixer?
Use it only if the pixel test shows the same point staying colored or bright. If the point stays black, forms a line, looks like a pressure mark, or appears as a ghosted image, skip the fixer and document the issue instead.
Why do I only see the dot on one color?
That can happen when one subpixel is affected, when the browser or app renders a color differently, or when dust or scaling makes a point easier to see on one background. Retest in fullscreen across red, green, blue, white, and black before naming the defect.
Is backlight bleed the same as a dead pixel?
No. Backlight bleed or glow usually appears as a wider bright area near an edge or corner, especially on a black screen. A dead pixel is a tiny fixed point.
Is burn-in the same as a stuck pixel?
No. Burn-in or image retention usually follows the shape of a logo, status bar, keyboard, or interface element. A stuck pixel is a single point or small subpixel behavior.
Can a browser pixel test prove warranty coverage?
No. It can help you collect evidence, but manufacturer policies vary by brand, model, region, warranty, defect count, and defect location. Use the test result as documentation, then check the official policy for the device.
How should I document a pixel defect?
Take one close photo and one normal-use photo. Include the relevant test colors, the device model, purchase date, whether the issue repeats, and whether cleaning or another browser or app changed the result.
Should I test a used monitor or phone before buying?
Yes. Run the pixel test on the actual screen, check black, white, red, green, and blue, then look for repeated dots, lines, pressure marks, burn-in, or edge glow. For resale, photos of clean test screens can also help document condition.