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Lighting The Darkness
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By John Jackman, October 1, 2002
Hardly a week goes by when I don't get an email asking some variation on the question, "How do I shoot at night in a dark room/basement/exterior?" Sometimes the questioner references a look from a specific television show or film. Every few months someone drops by my studio with a tape that looks like grainy surveillance video, and wails, "What did I do wrong?" The answers: not enough light in the darkness; not enough fakery.
Don't forget, ladies and gentlemen of the digital filmmaking revolution, that everything you do with DV is fake. It's a representation of reality, not reality itself. It's an attempt to simulate what's on the television screen, to create pictures and sounds that seem real to the viewer. And one task that requires a lot of fakery is making a scene look like it was shot in darkness.
It doesn't matter how sensitive your camera is. Forget the manufacturer's lux ratings - they are meaningless. Hollywood was creating convincing night scenes years before you were born with unbelievably slow film, as slow as 12 ASA/DIN, that required 25,000 to 30,000 lux for basic exposure. How did they do it? The same way we still do it. They used plenty of light to create a proper exposure, but in a stylized manner that conveys to the audience the impression of nighttime.
Getting the hang of this technique is not hard once you wrap your mind around one concept: You must light the darkness. Think of the times you've seen a film where someone hid in a closet or groped his way through a pitch-black cave. In reality, those scenes would be absolutely black, but in the film, you could see what the character was doing.
Lighting dark scenes involves several basic principles that are combined in different ways to create different specific effects. Some effects are more realistic than others. Some depend entirely on our experience seeing night scenes lit that way. Here are the principles.
- When you stop down a camera's aperture, a lot of light looks like less light.
- Moonlight is blue. It's reflected sunlight, and sunlight is usually rated at 5600 K (Kelvin). So a low-level, hard-light source with a blue tint positioned somewhere overhead is perceived as moonlight.
- The audience doesn't always wonder where a scene's light originates.
- Slashes of light - such as those from a cracked-open door - and pools of light - perhaps from a small light bulb - can provide effective partial illumination in a dark interior setting.
- Little if any part of a frame should be solid 7.5 IRE black. With a solid black background, an audience can't tell the difference between an illuminated subject moving to the right and a camera panning to the left. A bit of low-level fill thrown on the background, or unexplained sprinkles of illumination here and there in the background, adds texture that lets the viewers better interpret what they are seeing.
- Low-key lighting with a high contrast ratio between the key and the fill lights can convey darkness while still illuminating the subject for proper exposure. A key light set as a back light or kicker can leave the foreground subject in shadow while letting the viewer perceive what is going on.
Using these principles, I'll construct a few practical scenes as examples, starting with some exteriors.
A teenager, separated from his companions on a dark and foggy night, hears a strange groaning sound in the woods (see Figure 1). Because all teenagers in horror flicks are incredibly stupid, he goes into the woods by himself to investigate. I would have run the other way as fast as my stumpy legs would carry me, but I had to light the scene, so I stayed.
I placed a DigiMole 400 W (watt) HMI light (www.mole.com) behind the teenager and shined it through the woods. With the camera white-balanced to 3200 K, the HMI appears blue and looks like moonlight. If I had been using quartz lights, I would have added a 1/4 CTB gel (Color Temperature Blue gel) or 1/2 CTB, but not a full CTB because I didn't want to make my moonlight too blue. A deep blue color is unconvincing. I wanted only a little blue, just enough to remind the eye of moonlight.
I could have stopped there, but the scene had too much contrast. The tree trunks and teenager were brightly lighted on one side and solid black on the other. So I added a fill light.
In this case, I positioned a small soft bank opposite the HMI, but a little toward the camera side. I could have also used a frog, which is simply a fresnel or open-faced light bounced off a large piece of white foam core. The low-level soft light fill from the soft bank lets the dark side of the tree trunks and the teenager register on camera. They will have a low-level exposure with some detail and texture, about four stops down from the key.
Next I added some fog to the scene. This made the scene spooky and gave the light volume without upsetting the audience's perception of night. A simple glycol fogger, available from lighting and theatrical rental houses, positioned off camera did the trick. On the set, the resulting scene looked blindingly overlit, but viewed on a video monitor, the scene was effective.
Another scene from the same flick required different techniques. After the teenager foolishly enters the woods, he encounters a slavering, six-eyed monster with machetes for hands. The teenager runs in blind terror out of the woods, barely escaping with his life. At a nearby farmhouse, he tells a cranky farmer about his experience (see Figure 2).
In that scene, I exploited the unmotivated light scheme. I threw enough light onto the background trees so they'd faintly read on camera, but I lit the foreground fully without bothering to explain where the light came from. Is it a street light? A car light? The film doesnÕt reveal the source. Although the principal light is unmotivated, using it as a kicker preserves a nighttime feel even though we haven't explained the light's source.
The overall fill came from the same HMI as before, positioned about 25 feet above the scene. The camera was again white-balanced to 3200 K to make the HMI seem like blue moonlight. Off to the left I placed a 1 K Lowel DP (www.lowel.com) as a kicker and used a soft bank on the right to provide a little extra fill on the subjects
. As with the previous scene, the scene looked very brightly lighted to the eye but was very convincing in the camera view. Part of the success stems from white-balancing the camera toward blue, but the
other important parts are exposure level and cropping.
Let's explore the unmotivated light scheme indoors. In workshops, I sometimes show a scene from the Elvis Presley film GI Blues. It's a bedroom scene where Elvis sings a lullaby to a baby. The room was lighted in a typical Hollywood-formula fashion: effective, but not breaking any new ground in lighting design. The bed and Elvis are fully lit, while the rest of the bedroom is broken into a pattern by several blue-gelled lights with cookies. I re-created the scene in Figure 3.
The lighting scheme in this scene is anything but realistic. If this lighting scheme exploded in my bedroom while I was reading late at night, I'd be perturbed. But although it's artificial, the scheme works. The audience doesn't question it at all.
But with a little effort, I improved this stock Hollywood lighting. I used the same idea, but I gave the main light source some motivation. In Figure 4, a young German count writes a letter by candlelight.
The key light, off camera to one side, was far more powerful than can be explained by the small candle. On the opposite side, a low-level blue fill suggests moonlight while a low-wattage orange light provides the illumination from an off-screen fireplace. An assistant waved a cookie around in a random pattern in front of the orange light to create a flickering effect. The end result is convincing.
Now we'll tackle an exterior street scene. A main convention in lighting nighttime exteriors involves placing a strong light source, often blue in tone, just out of frame - off to one side, around the corner of a building, etc. The light can suggest moonlight or a streetlight, or it may be unexplained light coming from who knows where. When illuminating outdoor scenes in general and pavement in particular, pointing the light toward the camera but slightly lower lets you light a large area with a lower-wattage source. The light skips off the pavement as a specular highlight and appears much brighter than would the same light source if it was pointed away from the camera. When you try this technique, make sure the direct light doesn't fall on the camera lens or it will create a flare.
I used this skipping technique to light a street scene (see Figure 5). I placed an HMI up high and just around the corner of a building. The camera couldn't see the light itself, only the effect of the light. The camera was white-balanced to 3200 K, so the HMI appeared blue.
For a fill light, I placed a 1 K Lowel DP without a gel near the camera, and set it on wide flood. When the camera iris was set to properly expose the specular highlights from the HMI skipping off the pavement, the fill seemed dark and let viewers barely perceive detail in the alleyway.
Next I positioned two 1 K lights inside the building - one shining out through a window and one shining out through a door that opened as the talent walked past. These lights provided motivated pools of light for the talent to walk through.
Because I wanted to create the impression of warm, incandescent light coming from the building interior, I gelled these instruments with a 1/2 CTO gel (Color Temperature Orange gel), but I could have used a similar amber, or straw, gel.
Look at the diagram in Figure 5 and imagine the effect as the subject walks toward the camera. At every step, the light is different. At first, the subject is mostly backlit by the HMI, then steps into the light from the window, and then passes into darkness and becomes a silhouette for a couple of frames before someone opens the door of the building, allowing another stream of light to illuminate the subject. But because of the low-level fill, the subject is not totally dark, even when in silhouette. The audience will barely see the features and style of dress, and be able to perceive the texture of the wall of the building.
Those are the basics of setting up and shooting dark scenes. As you experiment with the principles I outlined, remember the fundamental rule: Somewhere in the scene, you must have enough light to properly expose your camera's CCDs. In other words, you must light the darkness.
Backlight: An instrument positioned directly behind and above the subject, aimed at the subject's back. To avoid lens flares, you must keep the backlight from shining into the camera lens.
Cookie: Common term for cucaloris, a board with a cutout pattern that is placed in front of a light source to break the light into a dappled pattern. Can be used to simulate dappled light under trees or accent a night scene.
CTB: Color Temperature Blue gel, a translucent sheet available in several grades that makes light from incandescent sources match the look of sunlight.
CTO: Color Temperature Orange gel, a translucent sheet available in several grades that converts sunlight into the look of incandescent light.
Fill light: Light used opposite the key light to provide low-level illumination in shadowed areas.
HMI: Halide Metal Inert, an efficient and expensive light designed to simulate natural daylight.
High key: Lighting scheme with the ratio of key light to fill light at nearly 1:1.
Key light: The main light source for a scene.
Kicker: A light positioned behind the subject and off to the side, opposite the key.
Low key: Lighting scheme with more keylight than fill light. The film noir genre uses a very low key lighting scheme, creating a shadowy, contrasted look.
Motivated light: Illumination that appears to come from a practical or a real light source, such as a candle, desk lamp, or street lamp.
Specular highlight: White area on shiny surface generated by reflecting light source.
Unmotivated light: Illumination that doesn't appear to come from a practical or real light source.
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