The area of the picture space nearest to the viewer, immediately behind the picture plane, is known as the foreground. An understanding of perspective developed in the early 15th century allowing painters to divide space behind the picture plane into foreground, middleground and background.
In the foreground the figures and objects appear larger than those in the middle- or background because of their apparent proximity. They are painted with greater detail than things farther away, since only at close range would such detail be visible.
Painters also employ tonal changes to indicate greater distance.