Gradient Test — Check Your Screen for Colour Banding
A gradient is the cruellest thing you can show a display. Any limitation in bit depth, any lossy chroma subsampling in the cable, any over-aggressive contrast setting — all of it shows up as visible steps where there should be a seamless ramp.
What people use the gradient test for
Find banding in your signal chain
Stepping in a smooth ramp usually is not the panel. It is more often an 8-bit or 6-bit link, a cable running YCbCr 4:2:0 instead of RGB, or a driver colour setting. This test tells you there is a problem; the settings menu tells you where.
Check shadow and highlight detail
The dark and bright ends of a greyscale ramp are where crushing and clipping live. If the darkest few steps look identical, your black level is too low; if the brightest few merge, contrast is too high.
Compare HDR and SDR handling
Run the ramp with HDR on and off. A big difference in how many steps you can distinguish tells you a lot about how the panel is tone-mapping.
How to use the gradient test
- 1Press F for fullscreen and set browser zoom to 100%.
- 2View at your normal distance — banding that is only visible with your nose on the glass is not a practical problem.
- 3Step through the greyscale, red, green and blue ramps.
- 4If you see steps, check the GPU control panel for output colour format (want RGB, full range) and bit depth.
- 5Then check the monitor's own OSD for aggressive contrast, dynamic contrast or overdrive settings.
Frequently asked questions
I see banding — is my monitor bad?+
Not necessarily. Check the signal chain first: set the GPU to RGB full range rather than YCbCr, use a cable rated for your resolution and refresh rate, and turn off dynamic contrast in the monitor's menu. A surprising amount of visible banding is created after the panel, not by it.
What is the difference between 8-bit and 10-bit?+
8-bit gives 256 levels per channel, 10-bit gives 1024. On a slow, wide gradient, 256 steps can be individually visible; 1024 rarely are. Many '10-bit' consumer monitors are really 8-bit panels using frame rate control to simulate the extra levels, which works well enough that most people cannot tell.
Do I need to install anything?+
No. Everything on whitescreen.studio runs inside the browser tab you already have open. There is nothing to download, no extension and no account.
Is it free?+
Yes, all of it, with no sign-up and no usage limit.