The browser says your device or monitor doesn't support HDR.
If you're on a laptop using an external monitor, try the built in monitor
or, try this site on your phone. Most phones support HDR.
If you have an HDR display this page lets you draw in HDR (colors brighter than #ffffff). Different monitors, phones, have different maximum HDR "headroom". (the amount brighter than "normal" they support)
This is a feature available to WebGPU and coming soon to Canvas 2D and WebGL.
All Macs, iPhones, iPads, and most Android devices support HDR.
- Safari in iOS 26, macOS Tahoe 26 "should" support this. (untested)
- For iOS 18 you can enable it in Settings→Safari→Advanced→Experimental Features→WebGPU and WebGPU HDR.
- For macOS, Chrome works, Safari Technology Preview does not.
- Windows Chrome and Edge support this.