Light Quality and Lighting Instruments

Figure 10-1 shows the kind of portable lighting kit that documentarians use. You can do acceptable interior work using only a 750-watt quartz soft light. Light is diffused or soft when it creates soft-edged shadows or no shadows at all. Diffused light has the same effect as scattered light arriving from a broad source. It throws shadows so soft that they are hardly noticeable. You can produce soft light from one of the spotlights on stands (see Figure 10-1) by shining its output through a large square of diffusing silk or fiberglass or by bouncing its light off an aluminized umbrella or a white wall or ceiling.

Open-face quartz lamps are light and compact for travel. Quartz bulbs have a long life and remain stable in color temperature, and their bulbs are small enough to provide fairly hard light. Their disadvantage is that light pours uncontrollably in every direction, making lighting a rather rudimentary exercise unless you have barn doors (adjustable flaps at the sides, top, and bottom, as shown in Figure 10-1) to stop light spilling in unwanted directions. If you are on a stringent budget, you can find useable, low-cost quartz worklights at hardware stores that function well to create bounce-light sources.

FIGURE 10-1 Lowel^® DV Creator lighting kit. (Image courtesy of Lowel-Light mfg, Inc.)

Light becomes hard or specular when it projects hard-edged shadows (Figure 10-2). Paradoxically, a candle, although of low power, creates hard light because its effective light source is small and it casts distinct, hard-edged shadows. If you want the kind of hard light associated with sunlight, you will need a focusing lamp or spotlight (Figures 10-3).

Safety warning: Lights that use quartz bulbs run very, very hot and involve safety issues:

• Let lamps cool before disassembling them after shooting.
• Use a wadded tissue to hold quartz bulbs. Never touch them; oil in your skin bakes into the quartz envelope, causing the bulb to discolor or even explode when it is turned on the next time.
• Never switch on an open-face lamp when someone is in range. This is when bulbs most often explode.
• Never let rain get to hot bulbs. Sudden cooling by water spots makes them explode.

Light-Emitting Diodes (LEDs)

Banks of LEDs are now quite powerful (Figure 10-4), and some are adjustable for color temperature or for changing light quantities without losing color temperature. They draw very little current, create no heat, and are safe and easy to use. You can carry a circle around the lens (Figure 10-5) for traveling shots

FIGURE 10-4 A 1 × 1 Litepanels ™ LED bank. (Photo courtesy of Litepanels, Inc.)

FIGURE 10-5 The Litepanels™ Ringlite™ Mini, with LEDs circling a camera lens. (Photo courtesy of Litepanels, Inc.)

that require some fill light. The Litepanels ™ LP Micro panel clips to the top of the camera and is particularly useful for fill light while shooting inside a car (Figure 10-6; www.litepanels.com), but not all participants will take being lit in this way in their stride.

FIGURE 10-6 The Litepanels ™ LP Micro LED panel on top of a camera. (Photo courtesy of Litepanels, Inc.)

Fluorescents

Though all fluorescents produce a broken spectrum, you can get tubes and compact fluorescent lamps (CFLs) from the hardware store that are marked with an approximate Kelvin temperature: warm white (3000°K or less), white or bright white (3500°K), cool white (4000°K), or daylight (upward of 5000°K).

Kino Flo produces banks of fill lights that give good light output, draw comparatively little current, and create minimal heat (Figure 10-7; www.kinoflo.com). Balanced to give daylight or tungsten color temperatures, they come on immediately, are silent (unlike the ballasts in most fixtures), and are even dimmable.

Calculating Consumption

To calculate power consumption in amps (rate of flow), divide your total desired watts (amount of energy consumption) by the volts (pressure) of the supply voltage. Here’s how to calculate the unknown third factor when you have two that are known. I’ve assumed you are using a 110-volt working supply. To calculate:

Amperes (A): W ÷ V ÷ A (Example: 2000 W ÷ 110 V ÷ 18.18 A)

Watts (W): A × V ÷ W (Example: 25 A × 110 V ÷ 2750 W)

Volts (V): W ÷ A ÷ V (Example: 4000 W ÷ 36.36 A ÷ 110 V)

When scouting locations for electrical supply, keep high current requirements in mind. Wherever you can, aim to spread heavy amperage loads over multiple circuits. Locate house fuse or breaker boxes, which will contain fuses or breakers for each circuit rated as 15 A, 20 A, 50 A, and so on. By killing one circuit at a time and mapping electrical outlets belonging to each circuit, you can plan to spread the electrical load; that is, you can power your lights from several circuits rather than overloading one. Make a note to bring the necessary lengths of heavy-duty extension cords.

An expensive mistake is to tap into a 220-V supply and blow one’s lamps. Arm yourself with an inexpensive little multimeter (combining voltage, resistance, and current) from an electronics store so you can check supply voltages. Use it to measure voltages for any heavy-consumption lamp powered from a long extension cord. A lowered voltage can markedly lower color temperatures.

At each location, determine whether an appliance, such as a refrigerator or air conditioner, is going to kick in during shooting and trigger a circuit overload or make a noise that intrudes on the sound track. If you turn off a refrigerator while shooting, remember to turn it back on before you leave, or face having to replace the fridge contents. A recommended reminder is to leave your car keys in the fridge.

Adding to a Base and Using a Key Light

In documentary you often have to work fast, so there is a simple and reliable solution to lighting interiors. Called adding to a base, it means first providing enough ambient soft light for an exposure, then adding some modeling by using a harder light source as a shadow-producing key. Here’s what to do:

• Baselight—If the base light is insufficient, provide your own by using a soft light or by bouncing hard light off a reflective wall or ceiling. This provides a good overall illumination but used alone will give a rather dull and flat (that is, comparatively shadowless) look. This may be just right for some dull, flat situations (hospital, classroom, office, etc.).
• Key light—The light providing highlights and casting shadows is the key light. From its pattern of light and shadow, the audience infers time of day, mood, and even time of year. When you add key light it must be motivated; that is, it must appear to come from a logical source. In a bedroom scene, for instance, you would position the key low and out of frame to produce the characteristic shadow pattern cast by a bedside lamp. For a warehouse scene lit by a bare overhead bulb hanging into the frame, the additional key light would have to come from above. In a pathology lab where the source is a light table, the key would have to strike the subject from a low angle. Using multiple key lights is a skilled business and without a lot of practice can lead to the dread trademark of amateur lighting—ugly, multiple shadows. When in doubt, keep it simple.
• Cheating—You can substantially cheat (creatively adjust) the angle of the key for convenience, for artistic effect, and for minimizing shadows on the background, providing you stay within the bounds of what looks credible. You can also cheat furniture and participants away from walls, so shadows are projected not on the walls but low and out of sight. To help with framing, you can cheat people closer together than looks normal in life—always providing you don’t compromise your participants’ sense of normality.
• Practicals—Lamps that appear in the picture are called practicals, but they seldom function to provide any of the lighting (Figure 10-8). Adjust a table lamp’s output so there is enough to register as a light but not so much that you burn out that portion of the frame. You can seldom use a dimmer to lower a practical’s output, as the tungsten filament turns very red. Instead, cut the light output by putting layers of paper or neutral-density (ND) filter around the inside of its shade.

FIGURE 10-8 A practical is part of the scene but usually contributes little to its actual lighting.

FIGURE 10-9 A flat-lit subject and the same subject side-lit. (Photos by Dirk Matthews.)

Key Light Direction and Backlighting

Folklore about taking photos with your back to the sun suggests that light is best falling on the subject from the camera direction, but this ensures a minimum of shadow area and removes evidence of the subject’s third dimension—depth. Interesting lighting effects on the human face begin when the key light’s angle of throw is to the side of the subject or even relatively behind it (Figure 10-9). When shooting by available light, you may be able to light your participants more interestingly simply by reorienting the proposed action in relation to the ambient lighting or by altering the camera placement.

Backlighting creates a rim of light that helps separate subject from background and gives highlights and texture to hair (Figure 10-10). Achieving subject/background separation is important in black-and-white photography but less so in color, where varying hues help define and separate the different planes of a composition.

Three-Point Lighting

Three-point lighting is a more advanced setup that is ideal for lit interviews. See Project 1-AP-3 Analyze Lighting (in the Appendix) for a study project with notes, diagrams, and frames from a documentary to illustrate the different lighting approaches.

Lighting Tests and Rehearsals

• Lighting tests—The only way to assess film lighting is to shoot test shots with a digital stills camera—preferably in the actual locations—and critique your results. If lighting is at all elaborate, a lighting rehearsal using a digital stills camera can obviate embarrassingly lengthy location lighting sessions—or worse, costly electrical failures.

• Backgrounds—Aim to shoot when possible against dark or book-covered walls. These absorb the light that would otherwise overpower light reflecting off your subjects. When this is impossible, keep light off the background walls, as we have said, by: (1) angling light; (2) using barn doors on your light sources to keep illumination off the subjects’ backgrounds; and (3) cheating participants away from walls so you can better control shadow and background illumination problems. Moving them away also distances them from sound-reflective surfaces and reduces sound reverberation problems.