If your camera (or the existing lighting) is moving, you will need to get into the wonderful world of motion tracking! You'll want to track masks/shapes that reveal the original lighting (or newly created lighting). This could possibly end up being many, many layers.
I once did a day-for-night shot that was a "superhero" on a motorcycle zooming through a college campus "quad" area. This included our stunt driver roaring under/through a clock tower at 80 mph. Super-fun to shoot, by the way.
Anyway, I had to make the two clock faces that we could see in the shot be lit up, the motorcycle headlight, all of the walkway lights (each one was three different kinds of light, the light/lens flare at the lamp's bulb itself, the cone of hazy light it cast downward, and the lighting on the ground), office/classroom windows in the building behind, and aesthetic lights on the sides of buildings. IIRC, it was over a hundred layers all motion tracked to either the camera's movement or the motorcycle. Fun stuff.
(Edit: I forgot to add, we were changing the beautiful yellow of the Triumph that the stunt guy was driving into a red color so that it would match our superhero's color scheme, so I had to track all of those layers/masks too!)
It was a really cool shot and then the editor basically destroyed all of my work by cutting the shot to strobe with the beat of the music so you could barely see it! (This was back on AE version 7, by the way. Before CS5 or any of the CC versions on an old Pentium 4 machine, if I recall correctly.)
Thanks for the response!
Could I simply duplicate the layer, brighten the bottom layer, then use the
pin tool to delete the lighted areas from the top layer to reveal the
brighter lighting from the bottom later?
If that's possible, how can this be accomplished?
Pen tool? Yes. Mask tracking would probably be useful here if things are moving.
It is hard to give advice without seeing the specific shot. Most shots require several different techniques. You can read up on some motion tracking techniques here.
I think this tutorial gives some advice on day for night work.
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