Background
Why smooth gradients break into bands
A smooth gradient from dark to light should look like one continuous ramp. Banding is when you can see distinct steps instead, like contour lines across a sky or around a light source in a dark scene. It happens when there are not enough distinct levels between two colors, or when a step in the image pipeline throws some of them away.
Bit depth: how many steps there are
An 8-bit signal has 256 levels per color channel, which gives about 16.7 million colors. A 10-bit signal has 1,024 levels per channel, or about 1.07 billion colors. A full black-to-white ramp across a 2,560-pixel-wide screen at 8 bits has one step every 10 pixels. That is normally invisible, but a subtle ramp, say from dark blue to slightly lighter blue, may only cover a dozen levels across the whole screen, and those steps become wide visible bands.
Many panels advertise 10-bit color but use an 8-bit panel with FRC (frame rate control), which alternates between neighboring shades to simulate the levels in between. Some budget panels are 6-bit with FRC. FRC usually works well, but it can add faint shimmer in dark gradients.
Where banding comes from
- The source itself. Heavily compressed streaming video, 8-bit images that were edited aggressively, and low-quality JPEGs often already contain the bands. The downloadable reference on this page lets you check another viewer or device against the same file.
- Color management. Converting colors between profiles in an 8-bit pipeline rounds values and can merge neighboring levels.
- Calibration in the graphics card. A calibration curve loaded into the GPU reduces the number of distinct output levels if the output is 8-bit without dithering.
- Display processing. Dynamic contrast, sharpness, and some picture modes stretch the tone curve and widen existing steps.
- OLED near black. Some OLED panels struggle to separate the very darkest shades and show blocky steps in dark gradients.
How to reduce it
- Check whether the bands are in the content: open the same file in a different app or on a different screen.
- If your monitor and graphics card both support it, set 10-bit output (NVIDIA: Output color depth; AMD: Color Depth) and keep the panel’s FRC on.
- Turn off dynamic contrast, black equalizer, and heavy sharpening in the monitor menu.
- If you calibrate, prefer monitors that store the calibration in their own hardware lookup table over adjustments in the graphics card.
- For video, players such as mpv offer debanding filters that smooth bands already present in the file.
Common questions
- Does banding mean my monitor is 6-bit?
- Not necessarily. Many 8-bit and 10-bit displays show banding when the source or the processing chain is the problem. Testing the same file in another viewer and checking your display settings is a better first step than guessing the panel’s bit depth.
- Why do I see banding in YouTube or Netflix skies?
- Streaming services compress video heavily, and smooth skies and dark fades are the hardest scenes to compress. The bands are usually in the stream itself, and a higher-quality stream often reduces them.
- Will HDR remove banding?
- HDR video uses 10-bit or higher encoding, which helps, but HDR also stretches brightness over a wider range. Poorly encoded HDR can still band, especially in dark scenes.