ABSTRACT
THE VISIBLE SPECTRUM In further examination of the electromagnetic spectrum that we discussed in Chapter 1, we are now going to consider only the narrow band of wavelengths that can be sensed or experienced by the photoreceptors in our eyes. This very narrow portion of the electromagnetic spectrum is known as the visible spectrum and simply forms a range of wavelengths to which our eyes are sensitive (Figure 1.2 in Chapter 1). Within the visible spectrum, the wavelengths can be further differentiated through the varying color responses that they elicit from our eyes. Most light sources like the sun or a lamp contain elements of all the individual wavelengths of the visible spectrum, with the combined result producing an overall color that is perceived as white light. In reality, this white light is actually a mixture of all the other colors or wavelengths. The visible spectrum can be observed through a prism that through refraction breaks a light source into its component wavelengths. The familiar rainbow of red, orange, yellow, green, blue, and violet is the product of each hue being separated from the others as an effect of their ever-decreasing wavelengths. Red is associated with the longest wavelengths while violet is associated with the shortest wavelengths.
