display test
Display Black Level Test
Use this to spot obvious black crush or overly raised shadow detail.
No accountLocal where possibleRetest anytime
Look for separation between the darkest patches without raising brightness excessively
CSS screen—
Viewport—
Pixel ratio—
Refresh estimate—
DeviceOK can display patterns and estimate browser frame timing, but visual panel defects still require your inspection and professional measurements require dedicated hardware.
Private by design
The pattern is generated locally.
Use the result as evidence, not a guess.
This test checks
- Near-black visual separation
- Shadow detail
How to read it
Room lighting and display settings strongly affect this inspection.
It is not a luminance measurement.