Aerial perspective

In this picture, the aerial perspective effect is emphasized by a range of mountains at different distances, photographed in a nearly contre-jour condition.

Aerial perspective, or atmospheric perspective, refers to the effect the atmosphere has on the appearance of an object as viewed from a distance. As the distance between an object and a viewer increases, the contrast between the object and its background decreases, and the contrast of any markings or details within the object also decreases. The colours of the object also become less saturated and shift toward the background colour, which is usually bluish, but may be some other colour under certain conditions (for instance, reddish around sunrise or sunset).

Aerial perspective as viewed towards a sunset, with the colour shifting toward red as a result of rayleigh scattering
Dai Jin, "Landscape in the Style of Yan Wengui", early Ming Dynasty (1368–1644); a Chinese landscape painting using atmospheric perspective to show recession in space
Frans Koppelaar, Landscape near Bologna, 2001; a painting featuring atmospheric perspective: distant objects appear paler, of lower contrast, and bluer than nearer objects.