Line sketch is any image that consists of distinct straight and curved lines placed against a (usually plain) background, without gradations in shade (darkness) or hue (color) to represent two-dimensional or three-dimensional objects. Line art can use lines of different colors, although line art is usually monochromatic.
Line sketch emphasizes form and outline, over color, shading, and texture. However, areas of solid pigment and dots can also be used in addition to lines. The lines in a piece of line art may be all of a constant width (as in some pencil drawings), of several (few) constant widths (as in technical illustrations), or of freely varying widths (as in brush work or engraving).
Line is an art element. Line in drawing refers to a type of mark that contains both a direction and a length. There are numerous varieties of possible lines, including curved, bent, thick, wide, broken, vertical, horizontal, burred, or freehand. Lines are frequently used to delineate shapes, forms and spaces. The representation of volume, edges, movement and patterns can all be created using line. Lines can create both 2D and 3D objects and figures. Line in drawing refers to a type of mark that contains both a direction and a length
Line art may tend towards realism (as in much of famous painter Gustave Doré's work), or it may be a caricature, cartoon, ideograph, or glyph.
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. Using either stippling or hatching, shades of gray could also be simulated.
One of the most fundamental elements of art is line. An important feature of 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.