In conjunction with linear perspective, artists frequently use diminishing contrasts of hue, value, intensity of color, and texture to achieve deep penetration of space on a two-dimensional surface. This is known as the infinite concept of space or atmospheric perspective. (See your textbook)
Create a composition on “objects in space.” Imagine the picture plane as the near side of a volume of deep space. Use the indications of space suggested in the preceding paragraph, and soften the edges of objects as they are set back in depth. The human figure may be used to help suggest the scale of objects in space. Foreground, middle ground, and deep space can be indicated by the size of similar objects.