Trapped! Actress Andrea Fellers backs into a chain link fence in the deep darkness. Behind her is a 650W Fresnel with 1/2 CTB high and off over her left shoudler. A 300W Fresnel helps to put a little backlight on the structure behind her and a 4'x 4 bank Kino Flo provides soft front fill.

Over the years, I've had a number of rather passionate discussions in the past about the color of moonlight. I recall one cinematographer who fervently asserted that he had read moonlight with a color temperature meter and it was around 4000°K. Although I disputed whether or not his standard color temp meter could actually get a reading off of moonlight, I didn't necessarily dispute the results. As the moon is nothing more than a reflection of the sun and it is not necessarily biased by ambient skylight, it seems logical that the moon would be a rather cool blue color temperature, but not quite as high as standard sunlight. However, people don't perceive real moonlight as blue. When you're out at night and you're standing in moonlight, it doesn't look like "blue" light — it almost looks black-and-white (which is a factor of the rods in your eyes, which are more sensitive to low light, but less sensitive to color wavelengths) or "silvery." I've never really been a fan of deep blue moonlight and I think it's become something of a visual cliché, but that's not to say that your personal preference for or against blue is right or wrong. I will generally cool my "moon" lighting slightly, if it's a tungsten unit and I'm shooting a tungsten balanced scene, then I'll probably use a 1/4 to 1/2 CTB on the moonlight to cool it off from the rest of the scene a bit. Often times I'll then desaturate that blue a bit in post production and pulling the color tends to create that more silvery monochromatic look. In any case, I find the front fill is best if it is more neutral/white and as close to your proper color temperature as you can get. 

In this shot, actor Ed Schofield is out in the West Virgina forest. In the deep background we have a 12K HMI Fresnel on a 6' parallel providing the backlight. It is half corrected with 1/2 CTO. Another 1200W HMI with 3/4 CTO provides the edge light while a 500W tungsten Fresnel bounced into a 4'x 4' piece of bead board provides the front fill.

This overall technique also applies for an interior scene. On my first 35mm feature as a director of photography, many years ago, I was confronted with a situation in which the main character was in his apartment and the bad guy kills the power. How the heck do I depict a scene in an interior location when there's no light?! The answer is, again, in the edge lighting. Using that same technique, create a hard edge on your talent to pull them out of the darkness. This doesn't necessarily have to even been explained or motivated. The audience generally accepts this without question. A soft front fill, underexposed, will help to bring out the details in the talent. This can even be a 1/2 light fill from one side of your talent's face to keep one side in more complete shadow. The third step in an interior is actually what the late, great, Conrad Hall, ASC called "room tone." This is often a light bounced into a white ceiling or a large white bounce card up against the ceiling and set to several stops below key to just slightly bring up the detail in the room. If the light is large enough (the light fills a large portion of the ceiling or a large bounce card) it will feel 'sourceless' and just provide enough information in the shadow details to make out an environment. When shooting a dark interior scene, this is generally the very first light I'll set up. Creating this overall base-level "room tone" sets the rough base level exposure for the rest of the scene and gives me something to work from.

One of the problems I've seen in lighting tutorials — including this one — is that they primarily address a stationary subject. One of my main objections to teaching classic three-point lighting is that it typically only works for a subject that stays in one place. In practice, that's rarely the case. If your subject is moving throughout a location the best technique is to create "pools" of light for the character to move through. Don't be afraid of having areas of darkness intermixed with areas of light. If your scene is the killer quietly breaks in through the front door, you might start with edge light out in the hallway and no fill on his face as he moves into the door. Then as he moves into the room he can move into darkness and then, perhaps into silhouette in front of a dim window as he reveals his murder weapon and then back into a pool of darkness before landing in the three-light night look near the victim's sleeping body. This variation in lighting creates mood and ambience and feels realistic. Just be sure to highlight the moments the audience needs to see to understand the story points and don't be afraid to vary your techniques.