- Google and Apple are adopting the ISO 21496-1 standard for gain map metadata used in HDR photos.
- This will allow HDR photos taken from an iPhone or an Android phone to be viewed as intended on any platform.
- ISO 21496-1 support is available in Android 15, iOS 18, iPadOS 18, macOS 15, and Chromium-based web browsers on Windows.
One of the best features of last year’s Android release was support for true HDR photography. Instead of simulating an HDR-like effect by stacking photos and applying computational photography tricks, phones running Android 14 or higher are capable of capturing true HDR photos using Google’s Ultra HDR image format. While Ultra HDR was a great advancement in mobile HDR photography, it had one big problem: a lack of cross-platform compatibility. Thankfully, that’s no longer a problem, as both Google and Apple have embraced a standard that makes HDR photos appear as intended on Android and iOS.
The way that Google designed Ultra HDR was quite clever. Rather than creating an entirely new format, Google instead based Ultra HDR on the nearly universally supported JPEG format. In fact, Ultra HDR images are just JPEG files that have an extra bit of metadata slapped onto them. That metadata takes the form of a gain map that, when applied on top of the base JPEG image, turns it into a HDR photo. Devices and apps that support HDR and know how to apply the gain map will see the HDR version of the photo, whereas devices and apps that either don’t support HDR or don’t recognize the gain map will see the SDR version of the photo.