Moving tests
This version does not play a moving pattern. A chase or a flash is easy to misread, and it is not a repair. If a mark only appears after something moves, check whether it is still there on a still black field. That still does not time the panel.
What the engine draws
A solid field is one CSS colour on a single element, or the same colour in a PNG. There is no watermark, brand tint, texture or CSS filter on that surface. The blue interface stops at the frame.
A smooth ramp is a canvas gradient between two hex ends, interpolated by the browser as sRGB. A stepped ramp is a set of flat bands. Each band is an exact RGB from the same formula as the legend.
Exact solid values
| Name | Hex |
|---|---|
| White | #FFFFFF |
| Black | #000000 |
| Red | #FF0000 |
| Green | #00FF00 |
| Blue | #0000FF |
| Cyan | #00FFFF |
| Magenta | #FF00FF |
| Yellow | #FFFF00 |
| 5% grey | #0D0D0D · RGB 13 |
| 10% grey | #1A1A1A · RGB 26 |
| 25% grey | #404040 · RGB 64 |
| 50% grey | #808080 · RGB 128 |
| 75% grey | #BFBFBF · RGB 191 |
| 90% grey | #E6E6E6 · RGB 230 |
Fullscreen
Enter fullscreen calls the Fullscreen API from your click. Esc, or the Exit button, leaves. If the browser cannot enter fullscreen, the colour still fills the page. Esc or Exit still leaves. That view does not claim to hide the browser’s own bars.
Left and Right move. Space moves forward when focus is not on a button. H shows help. P hides the field on a pause screen that is not a test colour. Controls fade after a short idle. Hide controls keeps them away until you tap, so you can look at the corners.
After a few minutes a note offers a pause, which matters more on OLED. Pausing does not prevent image retention. It only hides the field in this tab. If you leave the tab for several minutes, the field pauses instead of sitting there.
What the browser can report
On the homepage, a line can show viewport CSS pixels, device pixel ratio and whether fullscreen can be requested. Those numbers are what the browser exposes. They are not the panel’s native resolution and not a hardware certificate.
What we do not measure
- Brightness in nits, black level or contrast ratio.
- Colour accuracy, white point or a display profile.
- Response time, input lag or refresh rate.
- Dead pixels, by any automatic detector. There is not one.
- HDR. Every value here is ordinary sRGB.
Safety
No flashing repair mode. No instruction to press, massage or heat the panel. No surprise animation between colours, because a crossfade would invent colours that are not in the test.
Engine
Version 1.0.0. Updated 6 November 2026. The test runs locally. See the privacy page for storage.
Questions
Do you feature-detect browsers by name?
No. Fullscreen is requested from the Fullscreen API. If the browser will not enter fullscreen, the same colour still fills the view. The page does not show an error for that.
Why not estimate refresh rate?
A browser timer is not the panel’s refresh, and a background tab makes it worse. This version does not show a hertz figure.
Are the PNG files the same colours as the page?
The solid files are filled with the same hex values and marked sRGB. A smooth gradient on screen is still the browser’s interpolation. The downloaded ramp is a horizontal grey from 0 to 255.