HDR & Brightness Check — Wide Gamut, Backlight Bleed & Banding
Browser-based tool to detect HDR and wide gamut (Display P3 / Rec.2020) support and check brightness uniformity.
01
HDR & Wide Gamut Detection
Detect HDR and wide gamut support using the browser's dynamic-range and color-gamut media queries.
Current display
HDR output is not active
Color gamut
sRGB class
HDR
dynamic-range: high
Not supported
Wide gamut P3
color-gamut: p3
Not supported
Ultra wide gamut Rec.2020
color-gamut: rec2020
Not supported
sRGB
color-gamut: srgb
Supported
If HDR is disabled at the OS level (Windows "Use HDR" or macOS "High Dynamic Range"), results show as Not supported. If your browser does not support the dynamic-range media query itself, results will show as Unknown.
02
Wide Gamut Comparison (sRGB vs Display P3)
Compare the sRGB primary and the wider Display P3 primary side-by-side on the same card.
Left is the sRGB primary, right is the Display P3 primary. On a wide gamut monitor, the right side will appear more saturated. If you see no difference, your display is likely sRGB-class, or the browser/OS is not outputting in P3.
Red
sRGB
P3
Green
sRGB
P3
Blue
sRGB
P3
03
Gradient Banding Test
Display smooth gradients and look for vertical step-like banding to evaluate bit depth and output path.
If you can see vertical stripes (step-like banding) across these gradients, your monitor or output path is likely 8-bit. 10-bit output and HDR-enabled signal chains produce visibly smoother transitions.
Black → White
Black → Dark gray (shadow zoom)
Black → Red
Black → Green
Black → Blue
04
Brightness Uniformity & Backlight Bleed
Fill the entire screen with a solid color to visually inspect backlight bleed, light leak, and color uniformity.
Fill the entire screen with a solid color and inspect the edges and corners for backlight bleed, light leak, and color uniformity. Click the preview to go fullscreen, and press ESC to exit.
Click to go fullscreen
Limitations
This tool is intended for HDR compatibility detection and visual wide-gamut confirmation. Actual peak luminance (nits) and HDR performance tier (HDR400/600/1000) cannot be measured from a browser and require a dedicated colorimeter. Use this page to get a feel for HDR differences and to help dial in monitor brightness settings.