Colour & Gradient Test
Full-screen gradients, greyscale steps and flat colour fields — the patterns that reveal banding, crushed blacks, backlight bleed and colour tint. The companion to the dead pixel test, run entirely in your browser.
Or jump straight to a pattern:
In the test: click or → / Space for the next pattern · ← for the previous · H hides the caption · Esc exits.
How to use the colour and gradient test
This is the companion to the dead pixel test, and it answers a different question. That one asks whether any single pixel has failed; this one asks how good the panel is as a whole. Run it in a dimly lit room, from straight on and at arm's length, after your screen has been on for a few minutes — brightness and colour both drift while a display warms up, and a cold panel will fail tests it would pass ten minutes later. Turn off any night-shift or blue-light filter first, or every neutral grey will look orange and you will diagnose a fault that is not there.
What each pattern shows
The gradients should fade smoothly from one end to the other. Distinct vertical bands instead of a smooth fade is colour banding, and it usually means the panel is 6-bit and approximating the missing shades, or that a colour profile is mapping values badly. A little banding in blue is normal; obvious stripes across the greyscale ramp are not.
The greyscale steps put 32 flat blocks side by side, which is a harder test than a gradient because the eye cannot smooth over the gaps. Count the steps at the dark end: if the first few are indistinguishable, your display is crushing blacks and you will lose shadow detail in films and games. Same at the bright end for clipped whites. Both are usually a contrast or brightness setting rather than a defect, and both are worth fixing before you judge anything else.
The flat fields test uniformity. On white, look for patches that are warmer, cooler or dimmer than the rest — that is backlight clouding, and it is common on edge-lit panels. On black in a dark room, look at the corners: a glow that shifts as you move your head is IPS glow and is a property of the technology, while a bright patch that stays put wherever you look from is backlight bleed, which is a manufacturing fault and may be covered by warranty. On 50% grey, the whole screen should look genuinely neutral; a pink, green or blue cast points at the colour temperature setting or a bad profile.
A note on what a browser can show you
These patterns are drawn on your own screen and nothing is recorded or sent. Be aware that what you see passes through your operating system's colour management on the way, so this test tells you how your display is behaving as currently configured — which is the useful answer for spotting a bad setting or a failing backlight, but is not a substitute for a hardware colorimeter if you need calibrated, measured accuracy for colour work.
Also worth running on a new screen: the dead pixel test and the refresh rate test, and see what causes dead pixels and can you fix them.
