Rendering a CG Scene - An Introduction to Computer Graphics for Artists - page 223

Fig. 12.7 The same sphere rendered with a rim light and front fi ll ( a ), rim without fi ll ( b ), and rim
with fi ll and blue refl ector ( c )

may be used to create contrast with the color of the key light and heighten the structure
and depth of the resulting image. Without bounce light, most images would be very
fl at. With it, they acquire depth (Fig. 12.7 ).

12.5.4.3 Rim Light

Depending on your shot, you may want to highlight your subject with a hard outline
made of light. This is known as a rim light . A rim light is a high intensity light directed
at your subject from the sides, top, or back (Fig. 12.7 ). If angled properly, it will cause
a bright highlight to follow the contours of your subject, as if outlined by a glowing
brush. The only real trick about using rim lights correctly is to get their intensity and
angle right. If you do those two things, they should behave as you expect.

12.5.4.4 Fill Light

A fi ll light works a bit like a bounce light, but instead of passively refl ecting existing
light, fi ll light is created by secondary light sources (Fig. 12.7 ). Sometimes, to make
the light more even, a photographer will put a box around a fi ll light that has an
opening on one side covered by a fi ne white mesh. This disrupts light passing
through enough so that, when it emerges on the other side, it is diffuse or soft light.
This is an effective technique for illuminating a side of your subject indirectly, in an
illusion of a higher level of ambient light than is ordinarily present.

12.5.4.5 Refl ectors

When a photographer lights a scene, he will try to ensure that everything in the
scene is clearly lit, even if it is in shadow. This is accomplished by using lights of
different intensities in combination with other equipment designed to manipulate