Principle
Type | Contrast | Resulting Attributes |
Diagonal | Maximum | Emotionally Active Esthetically Dynamic Spatially In Depth |
Horizontal or Vertical | Minimum | Emotionally Passive Esthetically Decorative Spatially In Static |
The diagonal line has no equal in visual intensity. It suggests depth or movement. The periphery of the eye is very sensitive to movement or to any diagonal, so it calls for complete attention from the viewer.

That is why traffic signs designed to warn of hazards are diamond shaped, using diagonals.

Vertical and horizontal lines infer a static or decorative visual condition. An example is a top hat. It appears taller than it is broad, but this is an illusion.
To summarize, the diagonal is much more visually intense than the vertical and has much greater impact than the horizontal.
Examples
In architecture, the Parthenon in Athens is said not to have a straight line in it. In fact, curved lines are used in many cases to make the straight lines appear straighter.

For example, there are three terraces at the bottom of the Parthenon. If they were not curved, they would appear to sag, as they are three inches higher in the middle than at the ends. The builders of the Parthenon placed all the horizontal lines at the bottom, the vertical lines in the middle and the diagonal lines at the top. This creates a decorative design by making the lines appear all on one plane.

The Parthenon is a linear composition, as illustrated by the diagram at right. This points to an important principle: It takes only a small amount of diagonal to visually equal or offset a great amount of vertical, or an even greater amount of horizontal.
Many modern artists have experimented with the effects of line direction. Among the most important is Piet Mondrian. By showing how to eliminate the diagonal line, he showed the way to a whole new concept of art.

Mondrian said, “Any object can be interpreted in terms of horizontals and verticals.” To relieve the monotony of using only verticals and horizontals, he added small areas of primary colors, which he incorporated in his pictures.

Another place you can see the use of line direction is by comparing the automobiles designed in the 1950s and 1960s to the models from the 1920s and 30s.

The cars of the later period were designed by lowering the verticals, emphasizing the horizontals, and using curved lines to emphasize function.
Try it!
Earthquake! Click the buttons to show the effect of changing from Minimal to Maximum Contrast in Line Direction. As the horizontal and vertical lines are replaced by diagonals, the picture becomes more active and dynamic.
_________________________________________________
Choose a link to learn more about the Alphabet
The Elements | ||
Line | Line Direction | Shape |
Size | Texture | Value |
Color | ||
Other Topics | ||
The Attributes | Composition | The Picture Plane |
About the Authors | ||
Alphabet Home |
The Alphabet of Art is a service of TriskelionBooks.com, the home of fantasy and science fiction author Jack Massa. Jack developed this site based on manuscripts and illustrations by Robert J. McKnight. If you have comments on the Alphabet or this site, please contact us here.
Copyright 1997-2020 by Jack Massa. The Alphabet of Art and all information on this site may be freely copied and distributed without charge, provided proper acknowledgement is given to the authors and the Copyright Holder, including the URL of this web site.