2.4.3: Light and Lighting

 

Whether shooting film or digital, black and white or color, one of the most powerful tools a cinematographer has to work with is light itself; without light, there is no image, and there can be no cinema. But simply having enough light to expose an image is not enough. A great cinematographer – heck, even a halfway decent one – knows that their job is to shape that light into something uniquely cinematic. To do that, they must have a deep understanding of the basic properties of light. Four properties, to be specific: Source, Quality, Direction, and Color.

The source refers to both the origin and intensity of the light. There are two basic distinctions in terms of origin: natural or artificial. Natural light refers to light from the sun or moon (which is really just the sun bouncing off the moon, but you knew that), and artificial light refers to light generated from any number of different technologies, LED, incandescent, fluorescent, etc. Each source will have its own particular characteristics, exposing a shot in its own particular way. Artificial light allows a cinematographer an incredible amount of freedom to manipulate and shape the light. Scenes shot indoors on a soundstage can be made to look like daytime exteriors with enough artificial light. Scenes shot outdoors at night can also be augmented with artificial lights standing in for moonlight. But natural light can also be manipulated and shaped through filters, flags (large black fabric squares used to block off the sun’s direct light), and diffusers.

Each new scene will require the cinematographer to consider their light source and how they want to shape it. And a big part of that calculation is intensity. How bright is the source, and how is that going to affect exposure? We’ll discuss depth of field later on, but how much light a cinematographer has to work with affects how much (or how little) of the shot can be in focus and how balanced their exposure will be in the final image. Sometimes a cinematographer can get away with just using available light, that is, the light from the pre-existing fixtures in a location (also called practical lights). But more often, they want to control the intensity more precisely, so they use specialized lights to illuminate the scene from outside the frame of the image. The lamps and overhead lights you might see in a film or TV series are actually more props than true lighting sources. They indicate to the viewer where the light is coming from in a given shot – what cinematographers call motivating the light source and direction – but they rarely add anything to the exposure of the scene.

Check out this short clip:

The subject in the scene is lit by several bright artificial lights just off camera. The table lamp in the background is only there to “motivate” the light that illuminates the side of the subject’s face. But it’s really just a psychological trick. If you really think about it, a dim lamp behind and to the right of the subject should not illuminate his face at all, but our brain tells us, “Sure, that makes sense.” That’s because we really want to believe; we don’t want to think about a crew of people standing around bright lights while a camera records it all. We want to be fooled, and the cinematographer knows that.

The second property of light cinematographers have to think about is quality. This doesn’t mean “good” or “bad,” it’s more about how the light “feels” in the shot. The easiest way to think about quality is in terms of hard or soft lighting. Hard lighting is intense and focused, creating harsh, dramatic shadows. Soft lighting is more diffused and even, filling the space with smooth, gradual transitions from light to dark. The difference is actually less about the light on the subject and more about the shadows cast by the subject. Are the shadows clearly defined with a hard edge? You’ve got hard lighting. Are the shadows fuzzy, less clearly defined, or maybe even absent entirely? You’ve got soft lighting. Cinematographers can control the quality of light by adjusting the size of the light source and its distance from the subject. Typically, the smaller the light source and the closer to the subject, the harder the light:

The third important property of light is direction. Where is the light coming from in the scene? Not the source, what makes the light, but what direction is it coming from? Left, right, below, above? Each decision will affect the look and feel of a scene, and practical lights in the set design can help motivate lighting direction. A single overhead lamp in an interrogation room will motivate a hard light from above. Large windows can help motivate a soft, diffused light from one side of the room.

Cinematographers plan their lighting set-up for any given scene by thinking carefully about what direction the light is coming from, starting with the main source of illumination, the key light. The key light is usually the brightest light on the set, used to properly expose the main subject. But just one bright light will feel like a spotlight, creating unwanted shadows. So, they use a fill light, usually less intense and a bit softer than the key light, to fill out those shadows. But those two lights shining on the front of your subject can make the scene feel a bit two-dimensional. To bring some depth to the image, they use a backlight, usually a hard light that shines on the back of a subject’s head (also called a hair light), to create some separation between the subject and the background. The brightness of each of these lights relative to each other is known as the lighting ratio and can be adjusted for various different effects. This lighting setup is known as three-point lighting, and it’s the most basic starting point for lighting a scene:

Of course, three-point lighting is just that, a starting point. Really complex lighting schemes will require far more layers to the set-up. But even then, cinematographers will talk to their gaffers, electrics, and grips in terms of key, fill, and back lights.

The fourth property of light that every cinematographer must understand is color. And no, I don’t mean red, blue, and green light bulbs. I mean the subtle color cast that different light sources give off that will ultimately affect the exposed image. For example, a typical household incandescent light bulb uses a tungsten filament to produce light. That light usually has a warm orange glow to it. But a fluorescent tube light in a ceiling fixture gives off a cooler, bluer light. In fact, we’ve come up with a way to measure these differences using the concept of color temperature. Color temperature is measured in degrees Kelvin. The lower the degree Kelvin, the warmer or more “red” the light. The higher the degree Kelvin, the cooler, the more “blue” the light. The orange glow of a tungsten bulb is around 3200 Kelvin. Daylight is around 5600 Kelvin.

It can get a little confusing, I know. Check out this quick overview of the science behind color temperature and how we use it in cinema:

As should be clear by now, color temperature matters a great deal when a cinematographer wants to set a particular mood. For example, a romantic scene in a candle-lit restaurant should have a warm orange glow. Fortunately, you don’t need to rely on a thousand candles to achieve that effect. Most modern LED (light-emitting diode) lights can be adjusted according to color temperature. All you have to do is dial in 2000K to your key, fill, and backlights, and you get the equivalent of the warm glow of candlelight without the fire hazard.

Source, quality, direction, and color are the four most important properties of light cinematographers must master to create great cinema. Once we understand these same properties, we can start to understand how cinematographers combine them to achieve an effective lighting style in any given scene, film, or series. For example, by lowering or removing the key light and relying more on indirect, relatively hard fill and backlights, you create deep shadows and high contrast in a scene. As mentioned in Chapter Three, this style of lighting is known as low-key lighting (because of the lack of a dominant key light, not because it’s laid back), used to evoke mystery and even terror.

Check out this short video essay on one of the greatest living cinematographers, Roger Deakins, and how he approaches lighting style in his work: