Colour test
Colour problems are the ones people live with for years without noticing, because there is nothing to compare against. Solid fields show tint and uniformity; stepped ramps show banding — the point where your screen runs out of shades and starts drawing stripes.
The test opens full screen. Space — next · Arrow keys — back and forward · Esc — exit
Your browser blocked full screen. The test still works in this window, but a full-screen view is more reliable — try pressing F11.
Did the colours look clean and the ramps smooth?
What each pattern is for
Press space to move through the patterns, arrow keys to go back and forward.
Solid red, green and blue show colour uniformity and stuck sub-pixels. A field that is noticeably brighter at one side, or that shifts hue across the panel, indicates uniformity problems.
Solid white is the tint test. White is the field where a colour cast is most obvious, and it is worth comparing against a sheet of paper under the same light.
Solid grey at the midpoint is where uniformity problems show most clearly. Look for patches that are lighter, darker, or slightly coloured.
The stepped grey ramp is 64 discrete steps. You should see 64 distinct bands, evenly spaced. Uneven spacing means gamma is off; steps that merge at either end mean the same crushing the contrast test measures.
The RGB ramps run the same 64 steps for each channel separately. Compare them: if one channel bands more than the other two, or runs out earlier, that channel is the weak one in the signal chain.
The smooth gradient asks the browser for a continuous black-to-white sweep. This is the one where banding is a real finding.
Windows 11
- Night light must be off — Settings → System → Display. It applies a warm curve to everything.
- Auto colour management in Windows 11 changes how colour is handled system-wide. If it is on and colours look off in some applications but not others, turn it off and retest.
- Colour profile: Settings → System → Display → Advanced display → Display adapter properties → Colour Management. A wrong or corrupt profile is the most common cause of a persistent cast. Setting it to sRGB IEC61966-2.1 is a reliable way to rule the profile out.
- Graphics driver control panels have their own digital vibrance or saturation controls, and they override everything. Check NVIDIA Control Panel → Adjust desktop colour settings, or the AMD equivalent.
macOS
- Night Shift and True Tone both need to be off before you judge anything. System Settings → Displays.
- Colour profile is under the same panel. On an external monitor, a generic profile is a common source of a cast — try the display own profile if one exists.
- macOS is colour-managed end to end, so a wide-gamut display will show sRGB content correctly in Safari. In browsers that manage colour less carefully, the same content looks oversaturated. That difference is expected.
Telling a settings problem from a panel problem
The distinction is simple and it decides whether you should be adjusting or returning:
- A cast or brightness difference affecting the whole screen evenly is a setting, a profile, or a picture mode.
- A cast or brightness difference affecting one region — a corner, a band, one side — is panel uniformity, and no setting will fix it.
Uniformity problems are common and mild on most consumer monitors. They become a defect when you can see them on ordinary content rather than only on a full-screen grey field.
Common questions
What is colour banding?
A gradient that should be smooth appearing as a series of distinct stripes. It happens when the display, the graphics pipeline or the source material has fewer available shades than the gradient needs. Some banding on a stepped ramp is normal and expected — the ramp is drawn in discrete steps on purpose. Banding in the smooth gradient, where the browser is asking for every shade available, is the finding that matters.
Why does the smooth gradient look striped but the stepped ramp looks fine?
That is the informative combination. The stepped ramp is 64 deliberate steps, so seeing 64 bands is correct. The smooth gradient asks for every shade the system can produce; stripes there mean the chain is losing shades — most often a 6-bit panel using dithering, a limited-range signal, or a colour profile applying a heavy correction curve.
My screen has a yellow or blue tint. Is it broken?
Almost never. Check the obvious causes first, in this order: night mode or blue light filter, colour temperature setting on the monitor, colour profile in the operating system, and picture mode. A uniform tint across the whole panel is a setting more than nine times out of ten. A tint that affects one part of the screen only is a panel uniformity problem and cannot be adjusted away.
Can I calibrate my monitor with this test?
No. Calibration means measuring the light coming off the panel with a colorimeter and building a correction profile from it — an eye cannot do that and a web page cannot do it either. What this test does is find faults big enough to see, which is a different and more common need.
Why do the colours look different in another browser?
Browsers handle colour management differently, particularly on wide-gamut displays. If the same red looks more saturated in one browser than another, the browser that shows it more saturated is likely not converting from sRGB to the display profile. That is a browser behaviour, not a monitor fault.