It is a trick of the filmmaker.
Underexposed in-camera or darkened during post-production.
Daylight masquerading as night, with blue tint.
Friendship for love, or sex for passion.
I know both on this American night.
“Day for night” is a set of cinematic techniques used to simulate a night scene while filming in daylight. I learned about this deception when I saw Francois Truffaut‘s 1973 film, Day for Night whose original title is La Nuit Américaine meaning “American night” which is the French term for day-for-night shooting.