Physics of visibility visibility depends on the transmission of light through the atmosphere and the ability of the eye to distinguish an object because it contrasts with the background A change in contrast with viewing distance occurs for both dark, light and bright objects With dark objects, the atmosphere introduces light, called"air light", to the sight path, and the dark object appears lighter at increasing distance until it bleeds into the background at the horizon With light objects, light is lost from the sight path with increasing viewing distancePhysics of visibility • Visibility depends on the transmission of light through the atmosphere and the ability of the eye to distinguish an object because it contrasts with the background. • A change in contrast with viewing distance occurs for both dark, light and bright objects. – With dark objects, the atmosphere introduces light, called "air light", to the sight path, and the dark object appears lighter at increasing distance until it bleeds into the background at the horizon. – With light objects, light is lost from the sight path with increasing viewing distance