The Fill Light: To Lighten Shadows
Fill light adds light to shadows. When you look at a contrasty scene, your eye automatically
adjusts for differences in brightness. As you glance from a bright to a
shadowed area, the eye’s pupil opens up to admit more light. Film, however, cannot
make such adjustments—it can record detail and texture in brightly lit areas or in
deeply shadowed ones, but generally not in both at the same time. If important
shadow areas are much darker than lit areas—for example, the shaded side of a person’s
face in a portrait—consider whether adding fill light will improve your picture.
Fill light is most useful with color transparencies. As little as two stops difference
between lit and shaded areas can make shadows very dark, even black.
Fill light can also be useful with black-and-white materials. In a black-and-white
portrait of a partly shaded subject, shadows that are two stops darker than the lit
side of the face will be dark but still show full texture and detail. But when shadows
become three or more stops darker than lit areas, fill light becomes useful. You can
fix these problems by adding fill light, rather than try to lighten a too-dark shadow
prior to printing.
Artificial lighting often requires fill light. Light from a single photoflood or flash
often produces a very contrasty light in which the shaded side of the face will be
very dark if the lit side is exposed and printed normally. Notice how dark the shaded
areas are in the single-light portraits shown in Figures 21.10–15. You might want
such contrasty lighting for certain photographs, but ordinarily fill light would be
added to make the shadows lighter (see Figure 21.16).
Some daylight scenes benefit from fill light. It is easier to get a pleasant expression
on a person’s face in a sunlit outdoor portrait if the subject is lit from the side or
from behind and is not squinting directly into the sun. These positions, however, can
make the shadowed side of the face too dark. In such cases, you can add fill light to
decrease the contrast between the lit and shadowed side of the face. You can also use
fill light outdoors for close-ups of flowers or other relatively small objects in which
the shadows would otherwise be too dark.
A reflector is a simple, effective, and inexpensive way to add fill light. A reflector
placed on the opposite side of the subject from the main light bounces the main
light into shadow areas. A simple reflector, or flat, can be made from a piece of stiff
cardboard, 16×20 inches or larger, with a soft matte white finish on one side. The
other side can be covered with aluminum foil that has first been crumpled and then
partially smoothed flat. The white side will give a soft, diffused, even light suitable
for lightening shadows in portraits, still lifes, and other subjects. The foil side reflects
a more brilliant, harder light.
A floodlight or flash can also be used for fill lighting. A light source used as a fill is
generally placed close to the lens so that any secondary shadows will not be visible.
The fill is usually not intended to eliminate the shadow altogether, so it is normally
of less intensity than the main light. It can have lower output than the main light, it
can be placed farther away from the subject, or have a translucent diffusing screen
placed in front of it.
A black “reflector” is useful at times. It is a sort of anti-fill that absorbs light and
prevents it from reaching the subject. If you want to darken a shadow, a black cloth
or card placed on the opposite side of the subject from the main light will remove fill
light by absorbing light from the main light.