Raphael, The Colonna Altarpiece, Madonna and Child Enthroned with Saints, 1505Caravaggio, Madonna del Rosario, 1607
Heinrich Wolfflin was a 19th Century art historian whose work on the styles of Renaissance and Baroque painters uncovered tendencies which help us to make sense of the style and composition of a wide variety of paintings, both from these eras and from others. His approach is to define by way of comparison and contrast a handful of compositional devices which help us to make better visual sense of the works.
We start with the distinction between planar and recessional styles. The planar style is exhibited in the Renaissance painting by Raphael on the left. We start with the picture plane, which is the plane represented by the canvas itself, and then imagine planes parallel with the picture plane represented as extending back into space. The planar style is organized around relatively clear depictions of these planes, as we see in the Raphael, where the steps, the platform, and the backdrop of the throne each represent a different plane parallel to the picture plane. The sky is the plane that lies furthest in the back.
The significant contrast to the planar style is what Wolfflin calls recessional, as represented in the Caravaggio on the right.Here, figures are placed at an angle to the picture plane, meaning they recede into the depth of the picture space. Notice here how the arms extend through various diagonals, helping move us from the front to the back and the back to the front.