'''Why Hollywood Darkness Persists in Film'''

This persists in modern films, even in scenes actually shot at night, for a simple reason: Cinema cameras can't shoot in the dark worth a damn. Despite what some people tend to think, one cannot simply "turn up the sensitivity" on film or digital cameras, as film will result in incredibly distracting, obscuring grain and digital sensors will have even worse blotchy, color-fringed visual noise. The easiest solution is to simply use a lot of stage lights to bring the scene to a reasonable level of brightness and underexpose from there; blue is used since that's the tinge usually resulting from night on a full moon, and therefore feels the most "natural."