A line can be a mark made by a pen or drawing instrument or it can be any continuous mark that causes the eye to follow along its path. The viewer’s eye travels along the path of a line because a line is longer than it is wide. A line moves, and as it does so it indicates direction. A straight line leads the eye swiftly across the picture plane but the eye travels more slowly when following the path of a jagged line.
Lines appear in different ways. There are curved lines and straight lines. These can be long or short, thick or thin, ragged, sharp, light dark, simple or complex. Lines can be made from repeating similar elements, as diverse as dots people, in a lengthways direction. Lines can be used to create form, to give depth. Lines can be carefully controlled to create optical sensations and can be used to project feelings of sensitivity and strength.
When someone looks at lines they try to fit them into something related to their previous experiences; for example, scribbled may be interpreted as seashells, and a few lines can easily suggest an apple to someone who is familiar with this fruit. In some ways this can restrict the artist’s or designer’s freedom to make viewers see what is intended, although it does also open up new possibilities. Skilful artists and designers play with this tendency to see familiar forms in everything by using only a minimum of visual cluse to evoke a far more elaborate response. Care must be taken, however, that abstract designs and patterns do not unintentionally suggest unpleasant or ugly forms to the viewer.