The Fill,Back and Background
Lights

We've noted that the key light establishes the dimension, form and surface detail of subject matter. Although the remaining lights have less important roles, they are nevertheless important in creating an acceptable lighting effect.

The key light by itself (whether it's the sun in a clear sky or a focused quartz light in the studio) produces heavy, distracting shadows. The purpose of the fill light is to partially (but not entirely) fill in the shadows created by the horizontal and vertical angles of the key light.
   

The Fill Light

The fill light should be placed about 90-degrees away from the key light. This means that if you draw lines from the key to the subject and then to the fill light you'll create a right angle.

Although the fill can be positioned at any point from right beside the camera to 45 degrees away, it's safest to place the fill 45 degrees from the camera.

By lighting a full 90-degree area, an important margin of safety is created in case subjects unexpectedly move and camera angles have to be changed during the production. Having to stop a production to change the position of lights can represent a time-consuming and costly delay.

Although the horizontal angle for the key should be about 45 degrees, the vertical angle of the fill is less critical.

Generally, the fill is placed just above the camera, which means it ends up being slightly lower than the key. In this position it can easily do what it's intended to do: partially fill in the shadows created by the key light.

We've suggested that the fill light should be softer than the key. A soft light source is able to subtly fill in some of the key's shadows without creating a second catchlight in the eyes.

Note in the photo here how the shadow from the key on the cheek is only partially removed by the fill, creating a gradual "rounding off" of the key light on the cheek. This key-fill difference provides much of the perception of three dimensions that's desirable in a medium that's limited to two dimensions.   

Fill Light Options

A good choice for a studio fill light is a scoop, or a bank of color-balanced fluorescents. When doing on-location work these options are a bit unwieldy so a portable quartz stand light can be used with a diffuser. The diffuser not only softens the fill light, but it can appropriately reduce its intensity.

Outside, when the sun is being used a key, a reflector board can be positioned at about 90 degrees from the sun to reflect sunlight into the shadow areas.

Large white Styrofoam boards are often used for closeups in ENG work. There are also folding silver reflectors available that can reflect light much greater distances. Reflector boards can be clipped to a stand as shown here, or held by an assistant.

 

The photos here illustrate a subject with and without the use of a reflector fill in harsh sunlight.

If a key light puts out a wide beam of light, part of the key light illumination can be reflected onto the subject to act as a fill, as seen in this drawing.

The Back Light

With the key and fill lights out of the way, two points of three-point lighting have been covered.

The third point is represented by the back light. The function of the back light is to separate the subject from the background by creating a subtle rim of light around the subject.

The back light (sometimes called a hair light) should be placed directly behind the subject in relation to the closeup camera.

From an overhead perspective you should be able to draw a straight line from the lens of the closeup camera, through the subject, directly to the back light.

Although the elevation of the back light is often dictated by conditions, a 45 degree angle is most desirable.

If the back light is too low, it will be picked up by the camera in wide shots; if it's too high it will spill over the top of the subject's head, lighting up the tip of the nose creating "the Rudolph effect," after a well-known reindeer.

Compared to the key, a smaller, lower-wattage instrument can be used for a back light for two reasons. First, back lights are often placed closer to the subject than the key light, and, second, with subjects confined to a limited area like a chair the beams of many lights can easily be "pinned down" (focused into a narrower beam) to intensify the beam.

By using only back lights with no front lighting a silhouette effect can be created. This can be used for dramatic effect or to hide someone's identity. (Note the photo of the woman reading the script above.) In trying to successfully eliminate all front lighting—especially in an effort to hide someone's identity—watch out for reflected light from walls and the floor.

Outside the studio the use of back light (generally in the form of sunlight) can add depth and separation to subject matter. 

At the same time, strong back light without adequate front light can create an exposure problem—unless you intentionally want to achieve a silhouette effect.

Remember, on many camcorders there is a back light control that's designed to compensate (to some degree) for this exposure problem.  A careful balance between front light and back light can add a 3-D quality to scenes.

Background Lights

Background lights are used to illuminate the background area and add depth and separation between scene elements. (Keep in mind that a back light is designed to light up the back of subjects and a background light is designed to light up the front of backgrounds.)

Once the background light is added, the lighting setup is complete, as shown on the right.

Any type of light can be used as a background light as long as it provides fairly even illumination across the background, does not hit the central subject matter, and is at the right overall intensity.

If the background has detail or texture, you will want to put the background light on the same side as the key (as shown in the drawing above). This keeps the dominant light in the scene consistent.

Note in the photo above that you can see the effect of both the back light and the background lights.

This brings up the last major issue in formula lighting: the relative intensity of each of the lights. We'll cover that in the next module.

The film-411.com LIGHTING TUTORIAL

Where and How?

The ways to light any particular scene are as numerous as there are scenes to light, and it would be insane to try to cover even a third of them, so we're going to give you a basic lighting setup from which you can extrapolate. That should cover 'where' and 'how.' What we're not covering here are the types of lights that you could possibly use. Likely, you'll be limited by the light package that you rent and will have to make due, anyway.

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Imagine a detective sitting at a desk in his office. He's facing the door and there's a bookshelf right behind him. There's a lamp on the right side of his desk and a window on the opposite side. In walks a woman. She's got trouble-or is she trouble? There's our scene. We'll light the medium shot of the detective from the woman's POV. The camera is looking at him straight on, with the desk surface forming the bottom of the frame and just a little space over his head. We want the light to appear as if it's coming through the window and lighting the detective from frame left. The desk lamp is on and throwing a soft glow over the right side of the frame. Clearly, we'll put a light on the detective from frame left. That light will serve as our main light, our Key. We'll put the Key light up on a C-stand (the all-purpose stand used all over the filmmaking industry). The key should be covered with some diffusion, since a bare light is much too harsh for what we're looking for. The diffusion comes in various thicknesses, allowing us to decide just how direct we want the light. In our case, we'll use a piece of 'tough' white diffusion, simulating light from the outdoors, on a stand just in front of our light. So now we have a guy sitting at a desk lit by a window. Great. Of course, if you shoot this scene now, you'll have half of the man's face in total darkness (assuming that you meter the lit part of his face), because even though his lamp is on, its feeble glow is no match for the Omni spot you're throwing on his right (our left) side. So we'll put up another light, this time on our right, behind and above the desk light. We'll pull it back a ways and use some tough diffusion and an orange filter to soften the light and simulate the light from the lamp. The addition of the secondary, or Fill light, helps to control the depth of the shadows on our figure. Now metering the subject's face should reveal a difference of one stop or so. The one-stop difference will still register shadows on film but won't seem like black and white. You'll still have detail on the man's left side.

Am I done?

You could shoot with just the two lights. Addition of more lights, however, will make your subject appear more apart from the background and add some visual texture to the image.

The back light is a very important light in separating the subject from the background. By shining a light from behind the subject (usually suspended on a rig from the ceiling of the stage), you can gain the desired effect. Aim the back light at the crown of the subject's head, being careful not to allow any of the backlight to spill onto the desk, lest you get quite the strange effect.

The last thing you might want to consider is the bookshelf in the background. You can pretty easily add light in a soft wash across the bookshelf (with a Softlight, no less, one designed with its own reflector so it throws even, soft light on a subject), but this might be more simplistic than you'd like. You could also aim two small lights at the bookshelf at oblique angles, creating long fall-off and more interesting visuals. The effect would be somewhat like waves of light on the bookshelf, and if it's skillfully and discretely applied it can really add the final touches on your shot.

Conclusion

So you've lit the shot.

It's pretty easy to understand why a two-hour movie can take three months to shoot, isn't it? You've mastered the three-point light theory (Key light, Fill light and Back light) and lit a relatively straightforward shot.

Congratulations.