Hatching
Hatching (hachure in French) is an artistic technique used to create tonal or shading effects by drawing (or painting or scribing) closely spaced parallel lines.
Description
(It is also used in monochromatic heraldic representations to indicate what the tincture of a "full-colour" emblazon would be.) When lines are placed at an angle to one another, it is called cross-hatching.
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, and Albrecht Dürer in particular perfected the technique of crosshatching in both media.
Artists use the technique, varying the length, angle, closeness and other qualities of the lines, most commonly in drawing, linear painting and engraving.