Perspective is an important aspect in art work, used to make the piece appear more realistic and dramatic. Brunelleschi developed the theory of perspective as well as the three kinds that we have discussed; atmospheric, logical, and observed. .
Atmospheric perspective creates the illusion of depth with a gradual reduction in the brightness of color and detail in the distance of the painting. It is achieved by using less focus, along with bluer, lighter, and duller hues for the distant spaces and objects depicted in a picture. An example would be Leonardo Da Vinci's Virgin of the Rocks (p.638 22-1). There is a bluer tone to the top part of the sky and as you look through the rocks, the background fades and the mountains take on a foggier look. Those aspects give the painting great depth. .
Logical perspective, also known as one point perspective, creates the notion that when you are looking at anything from a distance, that object will disappear from view eventually, the vanishing point, and the objects placed on the lines will eventually disappear to. This is created by having lines within the painting, that if you took a ruler and finished drawing the lines, they would all meet at one certain place with the art work. A good example of this would be Masaccio's Holy Trinity (p. 604 21-13). This fresco has a vanishing point around Christ's feet. This was the first use of logical perspective in a painting and the important element is the attempt to recreate architecture illusion through perspective. .
Observed perspective is where you have the use of elongated objects and lines to make a space look larger, but there is no point where they all connect. The Merode Altarpiece (p. 576 20-11), can be used to show observed perspective. The lines in the ceiling as well as the elongated table and bench, all make he room appear larger. Another example would be Van Eyck's Wedding Portrait. The bed, and lines in the window and floor, give depth to the room.