CSS / #fff
Browser white
A page element at ordinary reference white.
Screen check
Can this screen show the full effect?
This browser cannot tell us whether the full effect is available.
If the images below look the same, you may be showing the standard version. This check can suggest whether the full Ultra HDR effect is visible, but it cannot certify your screen.
01 / White references
Start with a simple white comparison.
JPEG / SDR
Conventional image white
The fallback rendition every JPEG viewer can display.
JPEG / Ultra HDR
Ultra HDR image white
The brighter version shown by compatible software and displays.
02 / Brightness range
Look for separation between each patch.
The labels show the effect requested by the file, not a measurement of your display.
03 / Campaign example
Now compare it on a real creative.
Read the result carefully
This is a rendering test, not a meter.
LumaGain cannot measure nits, display calibration, operating system tone mapping, or ambient-light adaptation from a web page.
Screenshots flatten the result into the capture pipeline, so they cannot preserve what an HDR-capable display may show in person.
Rendering also depends on browser, operating system, display mode, brightness, power state, and whether the viewer supports gain-map JPEGs.