01
Start with a smooth gray gradient
Choose the full signal range and inspect the horizontal ramp. Select shadows or highlights to examine a narrower range where abrupt tonal jumps may be easier to see.
ToolsFree browser-based screen test
Gray Banding Test for Gradients and OLED Panels
Compare smooth gray ramps, deliberate grayscale steps, and uniform fields to distinguish gradient posterization from fixed panel banding.
Panel testsTest workspace
Use every mode and inspect the entire panel, including corners and edges.
Test pattern
Fullscreen controls hide automatically. Move the pointer or tap to bring them back; Escape exits.
Signal range
Gradient direction
Percentages describe the 0–255 RGB signal, not screen brightness or measured light output. These SDR patterns depend on browser color management and display settings.
F toggles fullscreen. Arrow keys switch modes. Escape exits.
How to use this test
How to check grayscale gradient banding online
02
Rotate the gradient and compare steps
Switch to a vertical ramp, then compare the stepped pattern. Boundaries in the stepped mode are intentional; a smooth ramp should not show similarly coarse jumps.
03
Separate tone steps from panel stripes
Switch to uniform gray. If a stripe stays in the same physical location across patterns, investigate panel uniformity; if it follows gradient tones, check the signal path.
What the result can tell you
Gradient posterization versus fixed gray panel banding
Coarse contours in a smooth ramp can come from display processing, color management, or limited signal precision. Fixed stripes on a solid field point toward spatial unevenness. Browser ramps alone cannot establish native panel bit depth.
Testing notes
The dark ramp uses RGB 0–32 and the highlight ramp uses 223–255; small tonal increments can still be visible.
Our PNG and canvas patterns use an 8-bit RGB signal. They cannot certify a 10-bit or HDR display.
Compare the same pattern in another browser and a local image viewer before changing hardware settings.
Gray gradient banding test questions
Are the stripes in stepped mode a defect?
+
No. That mode intentionally draws separate gray levels so you can compare them with a smooth ramp. Reduce the level count to make the reference boundaries clearer.
Why does the gradient look different in another browser?
+
Browsers, operating-system color profiles, HDR modes, and display processing can map the same RGB signal differently. Keep the setup consistent for comparisons.