Rendering a CG Scene - An Introduction to Computer Graphics for Artists - page 221

Fig. 12.5 In this “photoreal” ray traced render, its aesthetic qualities are more important than its
realism (Render courtesy of Malte Langheim)

All of this equipment is used because natural lighting conditions are almost never
good enough. This is as true outdoors as it is indoors. “Good enough” is a subjec-
tive aesthetic standard attached to the quality of images. This does not mean that
there are no objective criteria available to rate the quality of an image, but that the
technical qualities alone are not enough to make the difference between an average
image and a great one.
What this can mean is that photographers will adjust the lights in their scene to
create striking images that are highly unrealistic. They may not seem unrealistic
because the photos are accurate representations of the things depicted within them,
but they are unrealistic in the sense that most people aren't followed around by 20
lights, large foil covered refl ectors, and other lighting gear.

12.5.3 Photorealism

Sometimes the term photorealism is used to describe the level of quality expected in
a CG render. What does this mean? A photograph is the equivalent of a render but a
photograph will always be photographic regardless of quality. This is because a
camera can only produce a photoreal image. Strangely enough, some photographic
images are not what is meant by the term “photoreal.” This is because the term
describes something more specifi c than realism alone.
If it is possible for a photo to fail the test of being “photoreal”, then something
else is meant by it. When “photoreal” is used to describe 3D models before they are
rendered, it describes the credibility of the measurements and textures in the scene
(Fig. 12.5 ). It is improper to use the term in this manner however, because photos,