Colors become increasingly muted, less intense in the distance. Color and value contrasts are reduced in each succeeding plane as it recedes away from the viewer. Yellow is the first primary hue that drops out of the picture as the distance increases. The second primary color to disappear is red, leaving blue. Details diminish in the distance.
Edges become softer in the distance, as though slightly out of focus.
The slightest hint of linear perspective in a landscape moves the eye back in space. Proportions of every compositional element must diminish in a logical progression from foreground to background. Overlapping shapes and forms will succeed even if all else fails. Perspective Perspective is how an object moves through space. The size of things is affected by their placement on the picture plane.