Those Ugly Stripes in the Sky: What Causes Color Banding, and How HDR10+ Eliminates It
You’ve probably seen it without knowing what to call it: a sunset, a foggy hallway, or a plain gray wall that should look like a smooth gradient instead shows up as a series of visible stripes or rings, like a topographic map. That’s color banding — and it’s a direct result of how digital video encodes brightness and color, not a flaw in your eyes or your screen.
Why smooth gradients are actually hard to encode
Every digital video signal has to represent a continuous range of light — from pitch black to blinding highlight — using a finite number of discrete steps. Standard high-definition video does this with 8-bit quantizing: 256 possible brightness levels per color channel. That’s plenty for a lot of content, but it starts to break down exactly in the situations where brightness changes slowly and smoothly across a large area — skies, shadows, out-of-focus backgrounds. With too few steps to work with, what should be a seamless transition gets rendered as a series of visible bands, each one a slightly different shade standing out from its neighbor.
How HDR10+ avoids it
HDR content needs an even wider range of brightness than standard video, which makes banding a bigger risk, not a smaller one — unless the encoding has enough precision to keep up. HDR10+ supports quantizing up to 16 bits, several orders of magnitude more steps than 8-bit video, giving it far more room to represent a gradient smoothly instead of in visible increments.
HDR10+ also uses Perceptual Quantization (PQ), which spends more of its available steps in the brightness ranges human vision is most sensitive to, rather than spacing every step evenly. The two effects compound: more total steps, spent more efficiently, in exactly the parts of the picture — skies, shadows, gradual light falloff — where banding is most likely to show up.
It’s not just about resolution or bit rate
A common misconception is that banding is a streaming or compression problem that more bandwidth would fix. Higher bit rate helps preserve detail, but banding is fundamentally about how many distinct brightness levels the format can represent in the first place — a limitation baked into the color depth of the format itself, not the size of the file. That’s why HDR10+’s higher bit-depth ceiling matters even for content delivered at very high quality.
Independent confirmation
Technical reviewers have reached the same conclusion. UPERFECT’s technical comparison of HDR10 and HDR10+ notes that HDR10+ builds a smooth, nuanced and continuous tone curve based on scene pixel distributions that is free of banding artifacts — and that its tone mapping holds color ratios constant while adjusting only luminance, preserving the original hue instead of distorting it in the process.
Read UPERFECT’s full comparison of static and dynamic HDR metadata for more technical detail.