Lines are capable of leading the viewer’s eye through the frame in different directions, usually either towards or away from a point of interest. When you open a novel, for example, your eye has been trained to read from left to right from top to bottom. Imagery is different as the eye will grab at certain contrasting areas, yet still follow and ‘read through’ the image.
Composition should consider viewpoint as this may provide a ‘look down’ onto natural lines such as pathways that wouldn’t be seen from ground eye level. Arranging natural lines also requires consideration of where you wish to place emphasis in the frame, as a line can lead to a key subject. Multiple lines can provide a more complex effect that leads the eye back and forth, though complex compositions can become unpleasant to look at. Lines often lead from the bottom of an image, leading into the centre or key thirds.
Splitting a composition with a line can also have an unusual yet appealing effect. By dissecting one area from another, a line can have a significant impact. Central lines can act as divisions or pointers from one area of an image to another too.