Light Source: Hard Light, Soft Light

Jim Stinson
September 2003

Whether you're lighting a video with ten kilobucks worth of hi-tech hardware or making do with available light, you have two basic ways to go with each light source: hard or soft - either a high-powered beam with clean edges or else a softer glow that falls off gradually. How do you create hard or soft light? How do you control it? When do you use it and why? Before we attack these questions, we need to start by expanding our definitions of hard and soft light.

You create hard lighting primarily with a spot, which is a small light source with a reflector to bounce all the light forward, a moveable lamp to change its spread and intensity and often a lens to further tame and direct the output. The resulting light is highly directional and the light rays are almost parallel (though they do spread somewhat, like the light from a projector). It is that directionality that creates the hard effect. Because the light rays are somewhat parallel, they can be cleanly interrupted by a mask like a barn door or a flag (a large black rectangle held in place by a stand). This creates a relatively sharp, straight shadow where the light path is interrupted.

Hard light is distinctive from the center of the beam all the way to the edge. Since no civilian lights are as precise and punchy as these movie instruments, spotlights paint subjects with a heightened, dramatic look that's exciting and possibly glamorous. For the same reason, spotlighting can also look artificial.

You can create soft light with several kinds of instruments. In increasing order of softness, they are:

• Broads: long halogen lamps in fairly small, open, rectangular reflectors.
• Scoops: large reflectors shaped like halves of eggshells with the lamp at the bottom.
• Fluorescents: banks of high-quality tubes in very large, flat pans.

Immensely large light sources are also created by hanging lamps in huge globes like Japanese paper lanterns, or even floating them in gigantic translucent balloons, but you'll rarely see these esoteric lights outside big-budget productions.

In even the smallest shoots, soft lights may also be created by modifying hard spotlights:

• Aiming the lights backward into reflective umbrellas, which become large light sources directed toward the subject.
• Aiming them through translucent umbrellas, which act as silks to diffuse the beam.
• Encasing them in tents with large, square, white fronts and black sides.
• Bouncing them off large, white reflectors like foamcore board.

Each of these techniques simply converts a small hard light source into a large soft one.

All soft light sources are large, ranging from somewhat large (broads) to extremely large (fluorescent banks) and their light is not aimed by anything more precise than a reflective housing. As a result, their light output is not very directional and the light rays scatter and bounce a lot on their way to the subject.

Because their beams are so imprecise, soft lights are nearly impossible to edge-mask. Small broads may be fitted with barn doors on their two long sides, but bigger soft lights can not. In compensation, soft lights create far less obvious shadows (multiple shadows on backgrounds can be difficult to deal with) and their beam borders are very gradual. Because of this slow fall-off, little broads produce light that resembles civilian light bulbs and big pans can simulate the soft illumination of outside light through a window.

In fact, the beams of softer soft lights can actually wrap around the contours of a subject to an extent that seems unlikely, according to pure geometry.

In controlling soft light, your choices are few. You select a coverage area by aiming the light. To vary the light intensity on a subject, you have three options:

• Move the light closer or farther away.
• Rotate the center of the light slightly away from the subject to reduce beam intensity.
• In multiple lamp (bulb) units, switch individual lamps on or off.

As for masking soft light edges, there is little you can do. If you can place a soft light a long distance from the subject, and if you can get a large masking screen (up to 4x8 feet) propped up near the subject, you can block a beam edge fairly well. The trouble is, soft lights rarely put out enough light to allow you to place them well back from the subject.

So the obvious answer is, if you need to control light precisely, use a spot. Spotlight intensity can be varied by focusing the beam and by using screens in the front holder, but here, we're interested mainly in edge control.

The first line of attack is the four barn doors, which are black metal flaps hinged to the ring in front of the light. By positioning barn doors, you can chop the beam edges. For a moderately sharp edge, set the spotlight's lamp in its flood position and for a sharper cutoff, set the lamp to spot.

In general, the farther you position the mask from the light, the sharper the edge. You can clip gooseneck flags to the light with their black flaps as far as 18 inches out in front. Studio flags can be set several feet in front (if they're big enough) and can define an edge that's ruler-sharp.

Multiple flags are very useful when you can't mask an irregular area with just four barn doors locked in a plain rectangle. You can even cut foamcore boards into special shapes that fit the job exactly.

Sometimes, instead of using a spotlight's sharp beam pattern, you want to diffuse it somewhat. You can place rings of diffusion material in the front accessory holder; but that tends to turn the light into a very small flood. A good compromise consists of spun glass and wooden clothespins. Spun glass is simply angel-hair-thin, flexible fiberglass sheeting. To use it, open the top and bottom barn doors to 45 degrees each or wider and clothes pin the edges of the spun glass to them. The result is still a spotlight effect, but with the harshness taken off it.