Dead Pixel Test

Use color fields to inspect pixels, gradients and detail

This dead pixel test online for laptop screens and monitors combines solid colors with brightness steps, a contrast checkerboard and grayscale or hue gradients. Each pattern answers a different visual question. Solid fields make isolated dots easier to notice; gradients help expose visible banding; stepped shades help you compare distinguishable detail. Start with the controls above, then use this guide to record what you see and decide what to check next.

How to use the tool

1. Clean the screen using its manufacturer’s instructions. Remove obvious dust and reflections before treating a small mark as a pixel defect. Use a normal viewing distance and a comfortable brightness setting.
2. Choose Solid color fields or Dead pixel check, enter fullscreen and inspect red, green, blue, white and black. Examine the whole surface systematically rather than staring at only the center.
3. Use Prev and Next, or focus the pattern panel and press the left or right arrow keys. Press Escape to leave fullscreen when the browser supports it.
4. Try brightness steps, the contrast checkerboard, the grayscale gradient and the color gradient. Record the pattern, location and display settings whenever a repeatable problem appears.

Distinguish a pixel-sized dot from a larger patch

A dot that stays dark on white and several colored fields may indicate a nonworking pixel or subpixel. A dot that glows on black or remains one color across different fields may indicate a stuck subpixel. These are useful descriptions of observations, not a guaranteed diagnosis from this webpage.

For example, if you find a red speck near the lower-right corner, switch to green, blue, white and black without moving the window. Check whether the speck remains in the same physical place. Compare another input or the display’s own built-in diagnostic if available. A mark that follows page content is different from one fixed on the panel.

A broad tinted patch, darker side or glowing corner is not the same as an individual pixel fault. Compare from directly in front and then from a slightly different position. Viewing angle, room reflections and display processing can all affect large-area appearance. For a focused spatial check, compare the uniformity fields.

Read a gradient or brightness-step result

The monitor color banding gradient test gives you a continuous browser-drawn transition. Visible stripes can arise within the application, operating-system color handling, output settings or the display itself. Compare the same gradient in another browser before attributing every band to the panel. A screenshot can help identify a rendered pattern, but it cannot photograph a physical screen fault.

Brightness steps let you observe which neighboring shades remain distinguishable. If dark shades merge, check ambient light and picture settings. If bright shades merge, compare with excessive contrast or enhancement disabled. Change one setting, then return to the same pattern; changing several settings makes the cause harder to identify.

These checks do not return measured color error, gamut coverage, contrast ratio or brightness in nits. A colorimeter and an appropriate measurement workflow are needed when those numerical properties matter. The browser’s displayed colors also depend on profiles and the current SDR or HDR configuration.

Keep a useful record

Note the monitor model, input, selected resolution, brightness, browser and the patterns that show the symptom. Take a photograph if you need to document a physical dot or patch, while recognizing that camera exposure can exaggerate or hide it. Consult the manufacturer’s pixel policy for service questions; this page cannot determine warranty eligibility.

References: EIZO visual monitor tests.