I’ve just bought a new Samsung TV - model UE65TU7020KXXU - and I’m trying to change the gamma settings to HLG for use with Sky Q. However, when I go to the settings, the option is greyed out. I can choose 2:2 and BT.1886 but not HLG. I’ve got Input Signal Plus turned on too. Could it be something to do with my HDMI or something else? Thank you.
Try with the sky box disconnected or simply turned off. It may be a setting that can only be changed when a device is not sending a signal to the TV. Some HDMI related settings are like that on many TV brands including Samsung, LG, Panasonic and Sony from experience.