Basic Principles

• The basic principle of using parallel lines in a photographic composition is that the human eye will see two lines that are actually parallel as if they were coming together at some point in the distance. For example, a photo of a set of railroad tracks will make use of parallel lines, since the two railroad tracks will never get any closer together. When the viewer is looking at the photo, however, the lines will look like they are going to come together at some point. This visual illusion makes the picture seem to have depth when it really doesn't.
  
  

Infinite Vanishing Points

• The lens axis of a camera is an imaginary straight line running perpendicular to the body of the camera. If the parallel lines in a photographic composition are at a right angle to the axis of the lens, they will seem to lead off into infinity. This can be used to create a particular feeling in a photograph, by guiding the viewer's eyes into the distance and then appearing to go on forever.
  
  

Defined Vanishing Points

• When the parallel lines in a photograph are at any angle to the axis of the lens other than a perpendicular one, the lines will give the impression of coming together at a particular point (either in the photo or beyond it) and then vanishing. This technique can be used to direct the viewer's eyes to an object in the picture. For example, a set of railroad tracks can be shown leading up to a railway engine. The gaze of the viewer will be directed along the parallel lines to the object of interest.
  
  

Other Effects

• The effect created by including parallel lines in a photographic composition can be heightened by the use of a wide-angle lens, which results in a more-dramatic picture. The direction and angle of the lines also creates different feelings for the viewer. Diagonal lines, for instance, contribute to a feeling of motion and activity. Horizontal lines imply a sense of serenity. Vertical lines create a feeling of power or strength. Many photographers use a horizontal picture composition when working with horizontal lines and a vertical composition for vertical lines, but this is not a requirement.