Display Test Gradient banding test
Gradient banding test
Find out whether smooth gradients on your screen break into stripes (banding). You look at four smooth bars drawn with 16-bit precision, plus an example with stripes on purpose, and click what you see.
About 1 minute · Free, no sign-up · Results stay on this device.
Detected automatically
How the test works
The cards on this page show whether HDR is on and how your browser draws the page, for example “WebGPU, 16-bit float”. A short “Get ready” list asks you to use your usual picture mode and says whether HDR is on – on Windows it also warns when HDR is off, because browsers then send only 8-bit colour. On iPhone, where Safari can’t go full screen, it suggests Share → Add to Home Screen.
Then you see five horizontal bars. The top one is an example with 18 steps on purpose, so you know what banding looks like. The other four – Grey, Dark grey, Sky blue and Warm – are smooth ramps drawn with 16-bit precision. The instruction says whether your browser draws them in 16-bit or 8-bit, with or without HDR. Look along each bar and answer “No stripes”, “Only in the dark bar” or “In several bars”.
The result is “Smooth”, “Good” or “Visible banding”. “Good” means you saw only faint steps just above black. That’s normal, especially on OLED in a dark room: the eye is very sensitive just above black, so faint steps can show there even at 10 bits. To look at those shades on their own, try the black level test.
8-bit, 10-bit and what banding is
Every pixel mixes red, green and blue. With 8-bit colour, each of them has 256 shades; with 10-bit, 1024. Banding – also called posterization – is when a smooth gradient, like a sky, fog or a dark film scene, breaks into visible steps because there aren’t enough shades in between.
This test checks the whole chain, not the panel alone: the browser, the graphics driver, the cable and the monitor. Any of them can squeeze the picture into fewer shades. It also works the other way: a good 8-bit screen with dithering – a fine pattern that mixes neighbouring shades so your eye sees the ones in between – can look smooth too. So “No stripes” doesn’t prove the panel is 10-bit.
How to reduce colour banding
- Windows with HDR off: browsers send only 8-bit colour, even if the graphics driver is set to 10 bpc (bits per colour channel). If your monitor supports HDR, turn it on with Win + Alt + B or Settings → System → Display → Use HDR. Then try the HDR test.
- Picture mode: turn off “dynamic” or “vivid” modes and extra processing in the monitor or TV menu.
- Cable: use DisplayPort or HDMI 2.1. Older cables may not carry 10-bit colour at high resolutions and refresh rates.
- Graphics driver: check that it sends 10 bpc. NVIDIA Control Panel → Change resolution → tick Use NVIDIA color settings → Output color depth. AMD Software: Settings → Display → Color Depth.
- Browser draws in 8-bit: update it and turn on hardware acceleration (Chrome: Settings → System → Use graphics acceleration when available; Edge: the same switch under Settings → System and performance). Chrome and Edge work best.
Questions
How do I know if my monitor is 8-bit or 10-bit?
A browser can’t read that, and a smooth result doesn’t prove it. Check the specifications: many monitors sold as 10-bit are “8-bit + FRC”, which quickly alternates neighbouring shades to show 10-bit ones and often looks just as smooth.
Why do I see banding in videos but not in this test?
Streaming video and many images are compressed, and compression often removes the in-between shades before they reach your screen. This test draws its gradients live, so if they look smooth here, the banding is most likely in the video itself.
Is colour banding a defect I can return the monitor for?
Often it isn’t a fault in the screen – banding commonly comes from settings, the graphics driver, the cable or the source. If strong stripes remain in several bars after the fixes above, contact the seller – return and warranty policies differ, so check the seller’s or manufacturer’s terms.
Does the banding test work on a phone?
Yes, the bars show in phone browsers too, and the instruction says whether they are drawn in 16-bit or 8-bit. On iPhone, add the test to your home screen first (Share → Add to Home Screen) so it opens without Safari’s toolbars.
Check everything in 5 minutes
The full Display Test covers HDR brightness, black level, gradients, colours, motion, dead pixels and burn-in – one simple step at a time, with a report you can save as PDF.
More single tests
- HDR brightnessHow bright highlights get, and how much big bright areas dim.
- Black levelTrue black and the darkest shadow detail.
- ColoursStandard sRGB, Display-P3 or beyond.
- Refresh rateYour Hz right away, plus motion clarity.
- Dead pixelsDark or stuck dots on full-screen colours.
- Burn-inFaint shapes left by static images on OLED.
- UniformityPatches, darker edges and backlight bleed.
Every pattern is drawn live at your display's native resolution with exact brightness values – no compressed video. · PeakNits home · Music visualizer · Privacy · Statistics settings