305407 2026-01-13 11:23:30 -0800 HDR images render as SDR while CSS transitions are active 2026-05-06 09:43:49 -0700 1 1 1 Unclassified WebKit Layout and Rendering Safari Technology Preview Unspecified macOS 26 RESOLVED FIXED InRadar P2 Normal --- 1 greg323464 simon.fraser ap bfulgham sabouhallawa simon.fraser webkit-bug-importer zalan oldest_to_newest 2171506 0 greg323464 2026-01-13 11:23:30 -0800 When CSS transitions are active (even in elements below the image), an HDR gain map will render as just the SDR base image while the transition is active. Mouse in / out with the grid at this example page to see the issue in Safari: https://gregbenzphotography.com/gain-map-gallery/ 2171507 1 webkit-bug-importer 2026-01-13 11:23:36 -0800 <rdar://problem/168081525> 2171600 2 ap 2026-01-13 15:53:23 -0800 Thank you for the report! I do indeed see images sometimes falling back to SDR, although I'm not sure if it's while transitions are active. One way or another, this page works as expected in Chrome, and not in Safari. 2207505 3 simon.fraser 2026-05-04 21:12:21 -0700 *** Bug 314049 has been marked as a duplicate of this bug. *** 2207506 4 simon.fraser 2026-05-04 21:13:30 -0700 <rdar://163382580> 2207507 5 simon.fraser 2026-05-04 21:14:55 -0700 Pull request: https://github.com/WebKit/WebKit/pull/64240 2208148 6 ews-feeder 2026-05-06 09:43:47 -0700 Committed 312702@main (66b092fde2ec): <https://commits.webkit.org/312702@main> Reviewed commits have been landed. Closing PR #64240 and removing active labels.