Page 99 - Graphic Design and Print Production Fundamentals

Graphic Design 87

Figure 4.1 The Electromagnetic Spectrum

Figure 4.2 Visible Spectrum

We describe the temperature (relative warmness to coolness) of light in degrees Kelvin. Typical
daylight ranges from 5000 to 6500 degrees Kelvin. We use the labels D50 and D65 to indicate daylight-
viewing conditions at these temperature points.

Observer

The greatest complexity of the colour event occurs in the interaction with the observer. The science of
physiology, the study of the human body’s functions, provides half the story. Psychology, which provides
insights about the function of the mind, completes the tale.

We begin with how our eyes, our optic systems, respond to light. Trichromacy and opponency are the
key concepts.