Dark pixel-sized points
White drives the requested RGB channels together, so a fully dark point can stand out. Recheck the exact coordinate on red, green, blue, and grey before describing it as a possible dead pixel.
Bright-field visual inspection
White Screen Test
The white screen test provides pure white plus 90%, 75%, and 50% neutral fields. Fullscreen, hideable controls, a temporary reference grid, and zone labels help you inspect dark points, surface contamination, and broad brightness or tint differences.
Compare points and broad areas separately
How to use the white screen test
- Set a comfortable bright-field level. Lower the device brightness if white is uncomfortable. The test does not become more valid by forcing maximum output, and the page cannot know the setting you selected.
- Inspect pure white for fixed dark points. Enter fullscreen and scan in narrow rows. Keep a suspected point in the same screen coordinate; avoid confusing a tiny mark on the outer surface with a non-responsive pixel.
- Compare 90%, 75%, and 50% neutrals. A surface speck may remain visually similar, while some pixel or panel effects change contrast as the field becomes darker.
- Locate broad differences with overlays. Turn on the grid or zone labels only long enough to name a region, then turn them off. Overlay lines and text can bias a visual uniformity judgment.
- Cross-check with black and RGB. A dark point that persists through white and the primary colors deserves the pixel workflow. A broad warm, cool, or greenish area belongs in a uniformity comparison.
Three useful bright-field observations
What white screen test fields reveal
Surface dust and coating marks
A speck above the pixel layer can cast a dark silhouette. Change viewing angle and, if needed, clean only according to the display maker’s coating guidance. Do not press or rub a suspected point.
Brightness and tint zones
Corners or bands may look darker, warmer, cooler, or greener than the center. That is a panel-area observation, not a pixel count. Compare mid-grey and normal content from your usual viewing position.
A safer surface cross-check
Distinguish a speck from a fixed pixel
Keep the white screen test open and move your viewing position slightly without touching the display. A surface mark may change its relationship to the pixel grid or catch a reflection differently. A physical pixel location remains fixed within the image plane, although magnification, subpixel layout, and panel coating can make this hard to judge.
If cleaning is appropriate, follow the manufacturer’s instructions for that coating and power state. Never use pressure as a diagnostic or repair step. Afterward, compare the same point on white, RGB, and black. The browser presents evidence for your eyes; it does not inspect the electronics beneath the surface.
Use the reference grid briefly
Zone names make observations easier to record—such as “upper-right third”—but the grid is not a measurement layout and its contrast can change perception. Hide it before comparing brightness or tint. For numerical mapping, a defined instrument position and measurement protocol are required.