
1
1
Basic Principles
of Light
andVision
1.1 Properties of Light
It is imperative to begin by dening several terms used throughout the book that
will help the reader understand the properties of lamp technologies available and
how light affects an individual. In addition to the introduction of the basic prin-
ciples of light and vision, the reader may also refer to the Glossary where deni-
tions of the various terms are provided.
As seen in Figure1.1, visible light is just a small part of the electromagnetic
spectrum to which the human eye is sensitive and it includes waves with lengths
from around 380 nanometers (10
–9
m) to about 780 nanometers. ...