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
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.
His main concept is that the quantity, thickness and spacing of the lines will affect the brightness of the overall image, and emphasize forms creating the illusion of volume. Hatching lines should always follow (i.e. wrap around) the forms. By increasing quantity, thickness and closeness, a darker area will result.
An area of shading next to another area which has lines going in another direction is often used to create contrast.
