One more important detail is that human eyes respond very little to color with low illumination, so night scenes are in black & white with very little color. I don't know if there is a B&W node in Poser. What thing that will complicate is when the main object has direct illumination from the Moon (Moon behind the camer). In this case the object will have some color, but the buildings in the back will be in B&W.

No blue light, only grey scales. Blue illumination is used in movies, it creates a nice psychological effect associated with, night, ghosts, dreams, but no blue light in real life.

Stupidity also evolves!