The current HDR calibration tool is pretty lackluster ~ yes, you can set you peak HDR brightness, but there is no means of really figuring out to set SDR brightness such that it won't clip. So I ask if it could be improved to be able to let us properly figure out the right SDR brightness for our individual monitors. Something like how many games ask to you to calibrate until you can no longer see a difference in Windows HDR Calibration app is an excellent reference point ~ that is, on how to let us setup HDR properly: this video, timestamp included, https://youtu.be/xoo7sSpCn1Y?t=136 gives a great overview of what I'm asking for, I guess.
I didn't include a page for FALL because that value is more often than not completely ignored, and it does require blasting the user with a white fullscreen window... but giving a hint for what the max reference luminance should be sounds like a good enough reason to do it anyways.
*** Bug 507440 has been marked as a duplicate of this bug. ***
A possibly relevant merge request was started @ https://invent.kde.org/plasma/kscreen/-/merge_requests/429
Git commit f5a4548ba3d4fabb73e8063dfb7e9724e45b86be by Xaver Hugl. Committed on 04/11/2025 at 17:10. Pushed by zamundaaa into branch 'master'. hdrcalibrator: add a page for the maximum fullscreen average luminance This value is usually ignored by applications (and by KWin's own tonemapping too), but it can offer a good hint for what the maximum SDR luminance should be. M +16 -0 hdrcalibrator/hdrcalibrator.cpp M +8 -0 hdrcalibrator/hdrcalibrator.h M +103 -3 hdrcalibrator/ui/Main.qml https://invent.kde.org/plasma/kscreen/-/commit/f5a4548ba3d4fabb73e8063dfb7e9724e45b86be