Grayscale Banding and Panel Uniformity

A gray gradient is the most revealing pattern you can put on a screen, because it exposes problems a solid color hides completely. It also catches out a lot of people: what looks like a failing panel is very often the signal being sent to it.

What banding looks like

Instead of blending seamlessly from black to white, the gradient breaks into visible bands — flat strips of one shade with a distinct edge where the next begins. Mild banding shows only in the darkest steps; heavy banding turns the whole ramp into stair steps. In everyday use it appears as rings in a sunset, blocks in a dark film scene, or contour lines in a flat-colored background.

Why it is often the source, not the panel

Check the cheap causes before you blame the screen:

• Color depth. An 8-bit signal has 256 levels per channel, and across a wide gradient the gap between neighboring levels becomes visible.
• Driver output. Windows or your GPU driver may be sending a reduced bit depth, or a limited rather than full RGB range.
• Cable bandwidth. A cable or port that cannot carry your resolution and refresh rate at full depth will silently fall back to a lower one.
• Video compression. Streamed video bands badly by itself, so a clip is never a fair test.
• Picture processing. Dynamic contrast, black-level adjustment, and aggressive sharpening all crush nearby shades together.

Turn those off, confirm your output is set to full RGB at the highest depth the link supports, and re-run the Banding & Uniformity Check before drawing conclusions.

Uniformity and tint

Banding is about the steps between shades; uniformity is about whether one shade stays the same across the whole screen. On a flat gray field, look for regions that are brighter or darker than the rest, or that drift warm or cool — one edge slightly pink, the middle slightly green. Faint cloudy patches are the dirty-screen effect, most obvious when the camera pans across a hockey rink or football pitch. Every LCD has some variation, since a mid-gray is the hardest thing for a backlight and crystal layer to hold evenly, and this is what people mean by the panel lottery: two identical models can differ noticeably.

What is worth acting on

Settings and cables are free to fix, so exhaust those first. Genuine panel-level banding or a strong tint gradient that survives every source change is a defect of degree rather than a clear fault, which makes it awkward for warranties — manufacturers publish pixel thresholds, as collected in the manufacturer policy comparison, but rarely a uniformity standard. Your return window is usually the real remedy, so judge a new screen early with content you actually watch.

None of this involves individual failed pixels. If the gradient also shows a fixed dot that ignores the shade behind it, run the full test tool and read up on dead vs. stuck pixels.