A Survey of Color for Computer Graphics

A Survey of Color for Computer Graphics SIGGRAPH 2001
Introduction
The goal of this course is to provide a broad survey of the color disciplines that relate to
computer graphics. Color is an enormous field, with applications in almost every area of
life. The taxonomy I present is designed to match common applications in graphics. It is,
by definition, incomplete and superficial. Therefore, I base my presentation on standard
texts and references in the field of color as much as possible. My hope is that after taking
this course, you will know what there is to learn, and where to learn about it. If some of
the fundamental principles can be learned just from the presentation, that would be great
also.
These notes are a description of the material that will be presented in the course. They
include an extensive, annotated bibliography plus copies of the slides. Because of the
way the bibliography is structured and annotated, I did not feel that it was necessary to
cite the references from the notes text.
The course is divided into three areas: vision, reproduction and synthesis. The vision section
provides the foundations for understanding color and its applications. The
reproduction section discusses color media and color management. The synthesis section
is split into computer graphics rendering, color selection and color design.
Color Vision
In this section, I will discuss basic color vision, colorimetery and color appearance. The
reference I use for color vision is Brian Wandell’s Foundations of Vision, which is structured
in three parts: Encoding, representation 1 and response. What I call “basic color
vision” is essentially the encoding part of his taxonomy. Colorimetery uses these principles
to measure color. Wyszechki and Stiles Color Science is considered the standard
reference for colorimetery, though most of what is presented here can be found in almost
any color text. Color appearance is the response of the visual system to color. Mark Fairchild’s
Color Appearance Models is a recent book on color appearance that includes both
a complete description of color appearance as it is currently understood, and a survey of
computation models that are being developed to address this complex topic.
Basics
Light enters the eye as spectrum of colors, distributed by wavelength. This spectral distribution
function impinges on the retina in the back of the eye and is absorbed by the
cones. Human beings have three types of cones, which respond to different wavelengths
of light. These are called either long, medium and short wavelength cones, or, correspondingly,
red, green and blue cones. Each cone absorbs light and sends a signal to the
brain. That is, the spectrum of light is encoded into three values that correspond to the
amount of light absorbed by each type of cone. This is the principle of trichromacy—
human vision is 3 dimensional.
It should be clear that the actual distribution of the spectrum is only indirectly “seen” by
1 Brian’s representation section focuses on the visual pathways in the brain—I will not address these issues
at all.
Maureen C. Stone 4
StoneSoup Consulting