They use those stupid blue lights to simulate the moon. Never worked, that I thought.
(Note: William Cuthbert Faulkner once wrote a great book, The Light In August, which was neither about light, nor particularly about any August of record.)
In some of my favorite movies, economy dictated the quality of lighting, the number and placement of lighting fixtures. So where cost brought about the foreboding darkness, it also bleached some of the artistry, and care had to be taken in terms of audience perception.
In the original Friday the 13th, lack of light figured into the storyline, that the small production had an excuse not to drench with light even the narrow confines of its storyline. Hence, a beneficial limitation, in which a flood light could be utilized on and off in certain sequences, including the beheading, which was absolutely drenched in harsh directed light, opposite the waters of Crystal Lake.
Not all deaths were shown in that film; a more detailed discussion of the story would reveal the motivation there. What was shown, was often quite harsh, with realism and bloodless brutality highlighted, save for one: that of the camp owner, which was a trick of light, in which the glare of lighting hid the killer.
Bill's death had to read on film, had to be recognizable: he was impaled on a door, which swung open before the camera to reveal his dead body; we were to instantly recognize his condition. All f*cked-up. The tall chick died by obscuring light then, and not from the trickery of darkness: floodlights, which the killer used as effectively as John Carpenter and his Michael Myers used darkness.
There-in the trees and grass and canoes and several cabins are given to the viewer in silhouette, save for interior shots, which are harshly lit, and further for the sake of economy we are never shown the entire camp, never given a sense of any kind of layout, never afforded any kind of schedule of shots that would lend to the mapping of that rustic premises. So we have a schizoid, economical perview of only the most necessary camera views of the setting.
The original Texas Chainsaw Massacre gave us a fade-in from darkness that simulated sunrise. It gave the harshness of the Texas summer sun. But then came the sister and brother making a walk to their doom with little more than a flashlight. There was also the limitation of the film, but we are there afforded a pervading darkness that jibes perfectly with the expectation of the storyline.