The Vertical Line in Composition
In a composition, the vertical line is more important than any other. The vertical line separates man (upright) from animal (on all fours), can stand alone without any other support (unlike the horizontal and diagonal line) and demonstrates the direction of gravity.
To create a well-balanced vertical composition, the dominant vertical must be bisected by a horizontal or diagonal line to prevent the eye from quickly leaving the picture. For example, in the painting below by Kenyon Cox, notice how the implied horizontal line (the back edge of the chair and the position of the woman’s hands) bisects the dominant vertical line (the leg of the chair and the position of the woman’s dominant arm) in the composition.
In the painting above, by John Singer Sargent, observe how the dominant diagonal line bisects the dominant vertical line in the composition. This precise bisection of only two lines creates a strong sense of balance and sets up the design for repeated patterns and calculated parallel intervals throughout the entire compositional scheme.