White Screen Test
Inspect a white surface for pixel defects and uneven brightness.
Before you start
Use a comfortable brightness and briefly scan the white surface for dark dots or uneven areas. It can also serve as a simple light panel; adjust the display itself for comfort.
Tap or click the plain surface to show the controls. Hide controls for a clear view; tap to recover them, or press H or Tab. Exit with the Exit button or Escape.
How to use this test
- Use a comfortable display brightness and start the white surface.
- Inspect briefly for dark dots, smudges, or broad brightness differences; hide controls if needed.
- Recover controls with Tab or H and exit when finished. Adjust brightness on the device itself.
What to look for
A white background makes dark pixels and large brightness differences easier to see. Surface dirt or smudges can look like panel defects, so distinguish marks on the glass from fixed dots in the image. For photography, the screen can provide a convenient light source, with output determined by your display settings.
Know the limitations
This is CSS white, not a calibrated light source. The browser cannot measure luminance, color temperature, or certify uniformity. OLED brightness limiting, automatic brightness, reflections, and display processing may change its appearance.
If white dims or looks uneven
Automatic brightness and display processing can change a large bright field. Compare with normal content and a gray surface before deciding a patch is abnormal. This page does not bypass OLED brightness limiting or provide a calibrated light output.
Common questions
Is this a calibrated photography light panel?
No. It provides a white image, but output and color depend on the display. Use proper measurement equipment when accurate lighting or color is required.
Why does the white screen dim?
Your display may apply automatic brightness or OLED brightness limiting to large bright areas. This page does not control those settings.