So, we're in post production now and like everything else in this process, it's complex, and like the writing and production phase, many creative decisions are needed!
We had the trailer color corrected and graded (not the one we currently use) and what a truly eye-opening experience.
First choice, "what color theme would you like?"
Turns out for horror, there are three basic themes: red (yeah, for the blood), green (creates an uncomfortable experience for the viewer as well as the sense of death), and blue (more sci-fi feel, works great with night shots).
Here's two examples: (lower left image is "normal")