ABSTRACT
This chapter outlines the strategy for investigation and closes empirically by reporting initial progress toward the stated goals. A strategy for solving problems of animal coloration was laid out in Optical Signals. The chapter considers the range of possible functions of animal coloration, since it seems probable that most coloration is some kind of resultant compromise among many, often conflicting, selection pressures. It identifies the general principles that render coloration visually conspicuous. The chapter also outlines how differences in environmental light favor selection of different colorations for conspicuousness under different ecological conditions. Luminance measures approximately the human brightness sensation by weighting radiance according to a standard luminosity curve that approximates the spectral sensitivity of the human eye. Luminance, dominant wavelength, and excitation purity characterize a stimulus but do not measure conspicuousness as expressed by the visual contrast between surfaces.
