Monitor Colour Banding: Why Gradients Show Steps and How to Fix It

You're looking at a sunset sky, a dark game scene or a smooth wallpaper, and instead of a seamless fade you see stripes: distinct bands of colour with visible steps between them. That's colour banding (also called posterisation). Sometimes it's in the content and nothing on your side will fix it. Often, though, it's caused by a setting, a calibration profile or a signal format, and those are fixable. This guide shows how to tell which it is and what to change.

What banding is, and why it happens

Digital images describe each colour channel with a limited number of steps. An 8-bit signal has 256 levels per channel. Across a wide, slow gradient (a whole sky going from light blue to slightly darker blue), there may only be a few dozen distinct levels to spread across thousands of pixels. If nothing hides the boundaries between those levels, your eye picks them out as bands.

Banding appears or gets worse whenever something throws away levels along the chain from file to screen:

• The content was compressed or saved with too few levels
• The signal range or format is mismatched between GPU and monitor
• Colour correction, gamma changes or tone mapping squash levels together
• The panel itself struggles to show fine differences, especially near black

Dithering, which adds a fine, invisible noise pattern, is the usual way to hide the steps. Many GPUs, monitors and video players dither some of the time. That's why the same image can band on one setup and look smooth on another.

Step one: is it the content or the display?

1. Open a clean test gradient. Search for a "monitor gradient banding test" page, or create a full-screen black-to-white or colour gradient in an image editor at 16 bits per channel. If a clean gradient looks smooth, your display chain is probably fine and the banding is in the content.
2. Compare sources. Banding in one streaming show or one game, but not elsewhere, points to the content or that app's settings. Streaming services compress dark scenes heavily, and blocky banding in shadows is very common there.
3. Take a screenshot. If the banding is visible in the screenshot when you view it on another device, it's in the content or software rendering, not the monitor.
4. Try another device or input. If a laptop, console or second PC shows the same gradient smoothly on the same monitor, look at your PC's GPU settings.

Common causes and their fixes

Signal range and pixel format

This is the most common fixable cause on PCs. Graphics drivers sometimes default to a TV-style "limited" range or a YCbCr format over HDMI. In your GPU control panel, look for output colour format (choose RGB), output dynamic range (choose Full), and output colour depth (choose the highest available). Then make sure the monitor's own input range setting (sometimes called "HDMI black level" or "RGB range") is on automatic or set to full. If you can only get RGB at a lower refresh rate, your cable or port may be the limit. Our stuck at 60Hz guide covers the same bandwidth issues from the other side.

Colour depth: 8-bit, 10-bit and dithering

Choosing 10-bit output where your GPU, cable and monitor support it gives the pipeline more levels to work with, and it helps most in HDR. That said, a well-dithered 8-bit signal can look perfectly smooth, and an undithered 10-bit chain can still band if something downstream processes at lower precision. For the background, see our 8-bit vs 10-bit explainer.

Calibration-induced banding

Software calibration on many PCs corrects the image by adjusting the graphics card's output curves. Each correction means some of the 256 input levels get merged, and if the GPU doesn't dither afterwards, smooth greys can turn into steps. Large corrections, such as fixing a strongly blue panel or a wildly off gamma, make it worse. Options:

• Get close with the monitor's own controls first (colour temperature, RGB gain, gamma preset), then profile, so the software correction stays small.
• If your monitor supports hardware calibration, use it. Corrections are then applied inside the monitor, usually at higher precision.

Our hardware calibration vs ICC profile guide explains the difference.

Monitor picture "enhancements"

Dynamic contrast, shadow boosters (often called black equaliser or dark stabiliser), aggressive gamma modes and high sharpness settings all remap tones. That remapping can squeeze neighbouring shades together and create visible steps. Reset to a standard or sRGB mode, set sharpness to its neutral default, and turn the extras off. Our setup guide without a calibrator lists sensible starting values.

When it's the panel: VA, OLED and near-black

Some banding is a hardware trait rather than a setting:

• Near-black on OLED: very dark gradients can show blotchy steps, sometimes called near-black posterisation, because the panel is controlling pixels at extremely low light output. It's most visible in dark rooms and dark scenes. Firmware updates sometimes improve it.
• Dark greys on some VA panels: VA panels can handle very dark shades less evenly than IPS, which shows up as blotchy or stepped shadows.
• Local dimming on Mini-LED: zone transitions can look like soft bands or halos in dark gradients. That's a separate effect, covered in our local dimming guide.

For these, small adjustments help: avoid black-crush settings, set brightness a little higher in a dark room, and keep firmware up to date. But you can't fully "fix" a panel limit with settings.

Banding fix checklist

• Confirm with a clean gradient test that the display, not the content, is banding
• GPU output: RGB, Full range, highest available colour depth
• Monitor input range: Auto or Full (matching the GPU)
• Monitor enhancements off; sharpness at neutral
• Compare picture modes, including any sRGB mode
• Remove or redo a heavy software calibration profile and test again
• Check for monitor and GPU driver updates
• Use a certified cable if a full-quality signal format won't hold at your refresh rate