Answered
Conrad_CCorrect answer
Community Expert
January 25, 2024
Full Screen Preview seems to maintain its own background color that isn’t controlled in the preferences.
But you can change it using the same method that also works in the Loupe view or Develop modules: Right-click the background and change the color from the context menu that appears. (If you don’t have right-click set up on your Mac, Control-click instead.)

