Genius at work via oldhollywood:

Above: The partial set from Citizen Kane consists of a foreground doorway and the butler (Paul Stewart), while Kane (Orson Welles) stands on a distant soundstage floor. 

Below: The final, deep-focus image was completed with a matte painting by Chesley Bonestell. The live-action elements of the doorway in the foreground and Kane in the background were optically composited with a painted hallway, columns, and floor. The distant reflection of Kane on the floor was painted as well. 

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