I haven't even finished watching "Tremors" (1990, Ron Underwood) and I'm already quite struck by one remarkable thing: unlike most horror films, this one takes place almost entirely during the day. The effect is interesting, but campy. It had been done fifteen years earlier, of course, with "Jaws" (which includes more scenes in darkness, but which operates on the same principle of a visible surface concealing an invisible menace... Jaws does it better, of course...)
It all reminds me of another film that plays with the opposite construct -- "Pitch Black" (2000, David Twohy) sets the danger not in a typical darkness, but in a total void of light that is true to the title. All three films evince a very strong awareness of an important horror concept, not just that the unseen is more frightening than the visible, but the curtain we see in front of us is more frightening than the edge of the frame.
I ran in to this realization on a short film I recently directed. In the short, a character is brutally attacked by a large monster. When the scene was shot, it was staged in such a way that the monster consistently entered from off-camera. Sometimes a hand entered frame, sometimes a torso... and as it turned out, the effect seemed hokey. But when the monster emerged from the shadows, there was something much more menacing about it, something much more believable. (a lot of this realization is thanks to observations by my friend JB, who noted the effect in an early cut of the film).
In "Jaws", we see the water, and infer the shark beyond it. In "Tremors", we see the sandy ground. "Pitch Black" relies on our recognition of a very vivid, almost tangible darkness. These are the surfaces from which the terrors come. In many horror films, though, terrors emerge from around corners, or even from the edge of the frame -- from places that are not our focus, that we can not look at (the edge of a frame, after all, is nothing more than the difference between color, texture and light -- it is not a thing in itself, but a change of pattern that we are seeing). To see something tangible (a surface, physical or implied) makes the implied horror behind it seem more real as well.
-AzS
