Day for night
Simulator
AI generated demo image
Where the picture sits on the brightness scale. A convincing night keeps nearly everything low, with a very few bright points and no broad middle.
Turning noon into midnight
Day for night is not a filter, it is a sequence of decisions: how far down, how cold, how much colour to lose, how hard to crush, and above all what to do about the sky. Get one of them wrong and the whole thing reads as a dark afternoon.
Night is not just dark
Underexposing a daylight shot gives you a dark daylight shot. What tells an audience it is night is the combination: a cold cast, almost no colour anywhere, deep shadow with no detail in it, and one or two sources that are allowed to stay bright.
The sky is the giveaway
Eyes forgive a great deal, but not a bright sky. A daylight sky stays visibly brighter than everything under it even when the frame is five stops down, and reads instantly as day. Hold it down hard, or frame it out.
Keep one thing bright
Real night has sources in it: a window, a street lamp, the moon on a wet road. A frame where everything is uniformly dark reads as underexposed rather than nocturnal. Protect one highlight and let the rest fall.
Blue is a convention, not a fact
Moonlight is slightly warmer than daylight, not blue. Audiences read cool as night because a century of film taught them to, which is a good enough reason to keep doing it. How far you push it is a style decision.
Shoot for it
Day for night is far easier if the plate is made for it: backlight rather than front light, overcast rather than hard sun, underexpose in camera by a stop or two so the shadows have no detail to protect, and avoid the sky.
Where it falls apart
Shadows that point the wrong way for moonlight, green foliage that stays green, visible blue sky, and faces lit evenly from the front. Any one of them will undo an otherwise good grade.