Two-dimensional or three-dimensional objects are often represented through shade (darkness) or hue (color).Line art may tend towards realism (as in much of Gustave Doré's work), or it may be a caricature, cartoon, ideograph, or glyph.An important feature of a line is that it indicates the edge of a two-dimensional (flat) shape or a three-dimensional form.A shape can be indicated by means of an outline, and a three-dimensional form can be indicated by contour lines.[1] Before the development of photography and of halftones, line art was the standard format for illustrations to be used in print publications, using black ink on white paper.