A dark dot, a bright speck and the faint outline of a keyboard are different observations. Calling every mark a “dead pixel” can send troubleshooting in the wrong direction. Start by describing the shape, the backgrounds on which it appears and whether it stays in the same physical place.
Compare the appearance before naming it
| Observation | Possible category | Useful comparison |
|---|---|---|
| A tiny persistent dark point | Dead pixel or subpixel, surface dirt, or another local defect | Clean gently; compare white and all primary colors |
| A tiny bright or colored point | Stuck pixel/subpixel or another panel fault | Inspect black and change the background |
| A faint larger outline of earlier content | Image retention or uneven OLED wear | Compare gray and normal content again after rest or varied use |
| A broad patch or edge glow | Uniformity, backlight, viewing-angle or panel issue | Compare angles and brightness under consistent room light |
These labels describe common patterns, not a certain diagnosis from a browser. LCD and OLED technologies fail in different ways. One subpixel problem may affect only some colors; a point does not have to be black on every background to merit investigation.
Run a slow six-color inspection
- Wipe the display with a suitable cloth. Look for scratches or a mark on the screen protector before starting software tests.
- Open the dead-pixel inspection. Use fullscreen if supported, then hide the controls to inspect the area behind them.
- Start on white, inspect the suspect point, then compare black, red, green and blue. Use Previous to return to a color instead of relying on memory.
- Use gray to look for a larger retained shape or broad unevenness. Keep room lighting and display brightness consistent while comparing.
- Return to ordinary content. Note whether the issue affects everyday reading or is visible only in a special test condition.
The site only draws the intended colors. It cannot read the physical output of each pixel, count defective subpixels or decide whether a panel meets its manufacturer's tolerance. “No visible issue” is your assessment of the areas you inspected.
Retention can resemble burn-in at first
Temporary image retention may fade, while OLED burn-in is associated with uneven long-term wear. A faint old status bar or keyboard outline in a single session is not enough to determine which you are seeing. Compare after a period of normal varied content or rest, following the manufacturer's advice.
Apple's OLED display explanation describes both temporary image persistence and burn-in. It also explains that some viewing-angle color shifts are normal OLED characteristics. That context is useful, but it does not diagnose a particular device from a photograph.
Do not run a bright static pattern for hours to “prove” a defect. Avoid pressure-based pixel fixes, heating the display or aggressive flashing cycles. A browser utility cannot promise to restore damaged pixels or reverse uneven wear.
Use another camera for physical evidence
A screenshot captures the image the software intended to show. A physical pixel that cannot display that image usually will not appear defective when the screenshot is viewed on a different screen. Photograph the suspect area with another camera, showing enough of the screen to establish location and the background used.
Keep focus and exposure reasonably consistent across photos. Camera sensor noise, reflections and moiré can create misleading dots or stripes; include a written observation and compare the screen directly. Do not use a photograph alone to count subpixels.
Choose the follow-up that matches the symptom
For shade merging or broad banding, try the gradient and contrast-step patterns. If the image looks fine but taps fail, use the touch grid; the display and digitizer are separate parts of the experience.
For a new purchase or replacement panel, record when the defect was noticed and contact the seller or service provider about their own return and pixel policies. Thresholds vary; no generic “one dead pixel always qualifies” rule applies. A spreading dark patch, lines after impact or persistent severe unevenness deserves professional inspection. Use the used-phone checklist before treating a clean display test as a complete device inspection.