Airlight in Arizona
May 17, 2005
With only a quick glance at this picture, we know that the mountain ridges are all at radically different distances from us. But how do we know this? The more distant the ridge, the brighter and bluer it appears. We're so used to seeing this, in photos, paintings, or real landscapes, that usually we don't even consciously notice it. This brightening, technically known as airlight, is due to sunlight being scattered by the atmosphere -- the same phenomenon that makes the sky blue. The effect is more pronounced when looking toward the Sun, and when there's dust or haze in the air. Under certain conditions, airlight can even cause distant mountain ranges to completely disappear.
This photo was taken in March 2005, in Organ Pipe Cactus National Monument, Arizona.Related Links: