Shading in the context of Shadow volume

Line art or line drawing is any image that consists of distinct straight lines or curved lines placed against a background (usually plain). Two-dimensional or three-dimensional objects are often represented through shade (darkness) or hue (color). Line art can use lines of different colors, although line art is usually monochromatic.

Several techniques used in printmaking largely or entirely use lines, such as engraving, etching and woodcut, and drawings with pen or pencil may be made up of lines.

Hatching (French: hachure) is an artistic technique used to create tonal or shading effects by drawing, painting, or scribing closely spaced parallel lines. When lines are placed at an angle to one another, it is called cross-hatching. Hatching is also sometimes used to encode colours in monochromatic representations of colour images, particularly in heraldry.

Hatching is especially important in essentially linear media, such as drawing and many forms of printmaking, such as engraving, etching, and woodcut. In Western art, hatching originated in the Middle Ages and developed further into cross-hatching, especially in the old master prints of the fifteenth century. Master ES and Martin Schongauer in engraving and Erhard Reuwich and Michael Wolgemut in woodcut were pioneers of both techniques. Albrecht Dürer in particular perfected the technique of crosshatching in both media.

In printing, a key plate is the plate that prints the detail in an image.

When printing color images by combining multiple colored inks, the colored plates typically do not contain much image detail. The key plate, most often printed in black ink, provides the main lines, shading, and contrast, giving definition and sharpness to the image. In instances where black is not used, such as in some early two- or three-color processes, the key plate may use the darkest available ink. In these cases, the term "key plate" may also be referred to as "keystone".

Hachures (/ˈhæʃʊərz/) are an older mode of representing relief. They show orientation of slope, and by their thickness and overall density they provide a general sense of steepness. Being non-numeric, they are less useful to a scientific survey than contours, but can successfully communicate quite specific shapes of terrain. They are a form of shading, although different from the one used in shaded maps.

Hachure representation of relief was standardized by the German topographer Johann Georg Lehmann in 1799. Hachures may be combined with other ways of representing relief, such as shades, the result being a shaded hachure map; an example of such a map is the Dufour Map of Switzerland. Emil von Sydow designed maps with coloured hachures: green for lowlands and brown for highlands.