erception much easier.2) ATMOSPHERIC PERSPECTIVEThe air contains microscopic particles of dust and moisture that make distant objects look hazy or blurry. This effect is called atmospheric perspective or aerial perspective, and we use it to judge distance. In the song "America the Beautiful," the line that speaks of "purple mountains' majesty" is referring to the effect of atmospheric perspective, which makes distant mountains appear bluish or purple. When you are standing on a mountain, you see brown earth, gray rocks, and green trees and grass—but little that is purple. When you are looking at a mountain from a distance, however, water droplets suspended in the air bend the light so that the rays that reach your eyes lie in the blue or purple part of the color spectrum. This same effect makes the sky appear blue.3) TEXTURE GRADIENTAn influential American psychologist, James J. Gibson, was among the first people to recognize the importance of texture gradient in perceiving depth. A texture gradient arises whenever we view a surface from a slant, rather than directly from above. Most surfaces—such as the ground, a road, or a field of flowers—have a texture. The texture becomes denser and less detailed as the surface recedes into the background, and this information helps us to judge depth. For example, look at the floor or ground around you. Notice that the apparent texture of the floor changes over distance. The texture of the floor near you appears more detailed than the texture of the floor farther away. When objects are placed at different locations along a texture gradient, judging their distance from you becomes fairly easy.4) LINEAR PERSPECTIVEArtists have learned to make great use of linear perspective in representing a three-dimensional world on a two-dimensional canvas. Linear perspective refers to the fact that parallel lines, such as railroad tracks, appear to converge with distance, eventually reaching a v...
