A design element. A mark connecting two points.
Line is not necessarily an artificial creation of a designer; it exists in nature as a structural feature such as branches, or as surface design, such as striping on a tiger or a seashell. It can act as as a symbolic language, or it can communicate emotion through its character and direction. Lines can cause different mental impacts according to their variations and use. They can be active or static, aggressive or passive, sensual or mechanical. Lines can indicate directions, define boundaries of shapes and spaces, imply volume or solid masses and suggest motion or emotion, as well as create light and shadow and form textures and patterns. The use of line in combination results in the development of form and value, which are other elements of design.
However, line is not always explicit. It can exist by implication, as the edge of forms. We can speak of a horizon “line,” or the “lines” of a car or a fashion silhouette, even though we know there is no literal line present.
Line also communicates emotion and states of mind through its character and direction.
Horizontal lines are calm and quiet. They suggest feelings of rest or repose. Objects parallel to the earth are at rest in relation to gravity. Therefore compositions in which horizontal lines dominate tend to be quiet and restful in feeling.
Vertical lines suggest more of a potential for growth or movement. Vertical lines communicate a feeling of loftiness and spirituality. Erect lines seem to extend upwards beyond human reach, toward the sky. They often dominate public architecture, from cathedrals to corporate headquarters. Extended perpendicular lines suggest an overpowering grandeur, beyond ordinary human measure.
Diagonal lines suggest a feeling of movement, direction 0r more vitality. Since objects in a diagonal position are unstable in relation to gravity, being neither vertical nor horizontal, they are either about to fall, or are already in motion. In a two dimensional composition diagonal lines are also used to indicate depth, an illusion of perspective that pulls the viewer into the picture-creating an illusion of a space that one could move about within. Thus if a feeling of movement or speed is desired, or a feeling of activity, diagonal lines can be used.
Horizontal and vertical lines in combination communicate stability and solidity. Rectilinear forms stay put in relation to gravity, and are not likely to tip over. This stability suggests permanence, reliability and safety.
Curved lines do vary in meaning, however. Soft, shallow curves suggest comfort, safety, familiarity, relaxation. They recall the curves of the human body, and therefore have a pleasing, sensual quality. Deep, acute curves, on the other hand, suggest confusion, turbulence, even frenzy, as in the violence of waves in a storm, the chaos of a tangled thread, or the turmoil of lines suggested by the forms of a crowd.
The quality of the line is in itself a fundamental visual language, to an extent that cannot be claimed for any other single element. Its use is so universal that we are all profoundly sensitive to it. Even without an artist’s training, we can extract considerable meaning from the kind of line used in a drawing.