The lack of context is kinda funny. This page from 6 months ago is a clearer demonstration and explains the idea: "HDR‑Infused Emoji" https://sharpletters.net/2025/04/16/hdr-emoji/

Discussed on HN: https://news.ycombinator.com/item?id=43717606

Basically a lot of recent-ish devices will display this with extra brightness. A feature intended for example in cinematic contexts, but can easily become an annoyance if abused.

This is the most "why is this on the front page of HN?" post I've ever seen.

They don’t seem to do it anymore, but for a while the title on Disneyland.com would kinda sparkle in HDR when you loaded it on the right hardware/sodtware (safari on MacBook Pro for example). Was actually pretty subtle and animated out so it was more of a “wait, did I just see that?” sort of thing.

Some AI slop to let you pick any color and brightness: https://codepen.io/zamadatix/pen/VYerweP. Note: it does not attempt to clamp anything, so if you extend brightness beyond what makes sense in the color space or your display can't actually represent that color the color may shift. If things just appear white try lowering the brightness (and checking it's actually running in HDR at the bottom).

If you have an HDR monitor + the latest Chrom* based browser this should work out of the box on macOS/Windows. Other platforms/browsers you'll have to check the WebGPU + HDR standards support (which will be different for <canvas> than <video>) and may need to twiddle flags and/or wait for future releases.

It should tell you the active color space and range info at the bottom.

On my phone, all i see is empty white image. Is that supposed to be a joke or is my device/browser not supporting HDR?