Interior Lighting for Designers

trast in corridors, washrooms, lunchrooms,
lounges, and other meeting places. On most
worksurfaces, however, diffuse light distri-
bution is desirable to minimize highlights
and shadows.
Experience and memory also influence
our perception of objects. Through the
course of time, people have come to expect
midday sunlight to emanate from a concen-
trated source overhead, at an angle less
than 45° from nadir (straight down), and sky-
light to be a diffuse, multidirectional source.
When a lighting system alters the
expected direction of light, it changes the
normal relationship between highlights and
shadows. An unnatural impression results,
inducing mystery or anxiety (figures 3.27
and 3.28).
In practice, objects being exhibited or
photographed are often lighted from two

sides to reduce excessive shadows. One side

has a concentrated beam-spread to enhance

drama and function as the sun’s directional

rays; the other side receives diffuse illumina-

tion to soften shadows and replicate the sky’s

diffusing quality. The background may be

lighted separately to distinguish the object

from its surround and to add visual depth.

Glare and Sparkle

Excessive contrast or luminance is distract-

ing and annoying. This negative side of

brightness is calledglare. In the extreme,

glare cripples vision by reducing or destroy-

ing the ability to see accurately.

Glare is often misunderstood as “too

much light.” In fact, it is light coming from the

wrong direction, the result of an extreme

luminance within the normal field of view. The

difference between the high and low beams

BRIGHTNESS

Figure 3.27Bust of Lincoln lighted from above. Figure 3.28Bust of Lincoln lighted from below.