Color Banding / Gradient Test

How to look for banding

Each strip runs from black on the left to full brightness on the right in 256 steps, one for every level an 8-bit color channel can hold. The steps are drawn as solid bands with no smoothing and no dithering, so what you see is what your display makes of them.

1. 1

   Open it full screen in a dimly lit room and look straight on.

2. 2

   Scan each strip slowly from side to side. A smooth ramp should look continuous, with no edges standing out.

3. 3

   Watch the dark end. Banding usually shows first in the darkest quarter, where steps are closest together in light.

4. 4

   Compare the strips. Bands on one color only point to that channel; bands on all four point to the display or its settings.

What banding means

Banding is visible edges between steps that should blend. Posterization is the stronger version, where a gradient turns into a few flat blocks. Common causes are a panel that shows fewer levels than the signal carries, a picture mode that stretches contrast, or a limited color range mismatch between computer and display.

Many displays hide banding with dithering, a fast fine pattern that mixes two levels. That is why this test cannot tell you a panel's true bit depth: a dithered 6-bit panel can look as smooth as an 8-bit one. For the tone curve, use the Gamma Test; for the darkest and brightest steps, the Screen Contrast Test.

Where banding shows up in real use

Smooth skies, studio backdrops, fades to black and shadows in games are where banding is most noticeable. If a video shows bands that this test does not, the cause is more likely the video's own compression than the display.