Stuck subpixel changes intensity: what to check

A tiny red, green, or blue spot on your screen may look brighter at some times and dimmer at others. It can be hard to tell whether the subpixel is failing or the picture, brightness setting, or display connection is changing what you see.

Compare the spot against plain colors before trying to fix it. The Display Test can help you inspect colors, and the Stuck Pixel Fixer runs a fast flashing pattern that may help free a stuck pixel. Neither test can guarantee a repair.

Check the changing subpixel

1. Open the Display Test and look at the screen's color test. Note the spot's position relative to the screen edges, then check it on different solid colors.
2. Keep the same test color on screen for several seconds. Look for whether the spot's brightness changes while the rest of the image stays still. Avoid judging it while a video, animated page, or moving pointer is underneath it.
3. Change the screen brightness one step at a time, then return to the original level. If the spot changes along with the overall screen, note that. Also check whether automatic brightness or a display color feature is active.
4. After recording what you saw, try the Stuck Pixel Fixer briefly. Its fast-changing colors are an attempt to free a stuck pixel, not a test that can confirm the panel is healthy. Stop if the flashing is uncomfortable.
5. Return to the same colors and brightness you used at first. Check whether the spot has disappeared, stayed the same, or changed again.

A subpixel is one of the tiny red, green, or blue parts that combine to make a screen pixel. A fault in one subpixel can look like a colored dot or a point that changes brightness as the screen displays different colors.

What the result means

The spot stays in the same place on every test color

A mark that stays at the same physical screen position across solid colors is more consistent with a panel pixel or subpixel problem than with ordinary page content. Note which colors make it brightest or hardest to see. That pattern can help when you contact the screen maker or a repair shop.

The spot changes when the test color changes

This can happen because each subpixel contributes differently to different colors. For example, a red subpixel is easiest to see on a dark or contrasting background. Compare like with like: use the same color, brightness, and viewing angle each time. A change in visibility alone does not prove that the pixel is recovering or getting worse.

The spot changes when screen brightness changes

Brightness controls can alter the whole panel and may make a small defect easier or harder to notice. If the apparent change follows an automatic brightness adjustment, content-based dimming, or a color mode, turn that feature off temporarily and repeat the comparison.

The mark moves, appears in a screenshot, or changes with the page

A physical pixel cannot move around the panel. If the mark follows an image, pointer, or window, look for a graphic, overlay, or software issue instead. If it appears in a screenshot, the mark is likely part of the image being rendered, not a defect in the physical display panel.

The mark remains after the flashing pattern

The Stuck Pixel Fixer may not change the result. A pixel that stays visible on the same solid colors is not guaranteed to respond to flashing. Repeating the pattern for a long time is unlikely to provide a reliable diagnosis, so compare the display again under the same conditions instead.

How to rule out display settings and connections

1. Turn off automatic brightness temporarily. On Windows 11, check Settings › System › Display › Brightness for automatic or content-based brightness options, if your display offers them. On macOS, check System Settings › Displays for automatic brightness or True Tone, if available. Repeat the color check at a fixed brightness.
2. Use one display mode while comparing. On Windows 11, open Settings › System › Display › Advanced display and note the selected refresh rate. Keep it unchanged for the comparison. On a Mac, use System Settings › Displays and leave the resolution and refresh settings fixed.
3. Check whether the mark is in the source image. Move the window or change the displayed page. If the mark moves with the content, close that page or app and inspect another. A panel defect stays in the same physical location.
4. Reconnect an external display. Check that the video cable is firmly seated at both ends. If practical, try another cable, port, or computer. A connection fault can cause image artifacts, but it generally will not behave like one consistently fixed subpixel.
5. Restart the computer. A restart can clear a temporary graphics or app problem. If the spot remains in the same screen position on the startup screen and in the color test, a software cause is less likely.
6. Avoid pressing or rubbing the spot. Pressure can damage the panel or create more defects. If you choose to run the flashing pattern, use it briefly and stop if it bothers your eyes.

When it is probably a panel fault

If the same small mark stays in one place across different pages, solid test colors, and a restart, the display panel is the likely source. For a laptop, check the warranty or contact the manufacturer before paying for a repair. For an external monitor, ask the seller or manufacturer whether the defect qualifies for service. Pixel policies vary, and a browser test cannot determine warranty eligibility.

For a useful record, note the display model, the mark's position, the colors where it is most visible, and whether it changes with brightness. Do not rely on a screenshot alone to show a physical pixel defect.