Selected Bibliography Architectural Graphics | Page 134

HATCHING ' Hatching consists of a series of more or less parallel lines. The strokes may be long or short, mechanically ruled or drawn freehand, and executed with either apen or a pencil on smooth or rough paper. When spaced close enough together, the lines lose their individuality and merge to form a tonal value. We therefore rely primarily on the spacing and density of lines to control the lightness or darkness of a value. While thickening the linear strokes can serve to deepen the darkest values, using too thick of aline can result in an unintentional coarseness and heaviness of texture. \ ~. ~ ~··: '1--- ~ "---------. ~" ·.•·"'~·-. ~. --.___~ ... __ ...._ ' ;~ ·' ,, ~--- - - _ _. • The most flexible freehand technique for hatching utilizes relatively short diagonal strokes. To define aprecise edge, fix the beginning of each stroke with slight pressure. Feather t he ends of the strokes to depict curved surfaces, atexture gradient, or subtleties of light and shade. When extending atonal value over a large area, avoid the effect of banding by softening the edges and overlapping each set of strokes in a random manner. By applying add itional layers of diagonal strokes at only slightly different angles to the preceding sets, we can build up the density, and therefore the tonal value, of an area. Maintaining the diagonal direction of the strokes in t his manner avoids confusion w the underlying drawing ith and unifies the various tonal areas of a drawing composition. -- The direction of hatching can also follow the contours of aform and emphasize the orientation of its surfaces. Remember that direction alone, however, has no impact on tonal value. With texture and contour, the series of lines can also convey material characteristics, such as the grain of wood, the marbling of stone, or the weave of fabric. • Do not attempt to produce arange of values by varying the grade of lead. Be careful not to use too dense a grade of lead or press so hard that the pencil point embosses the drawing surface. • Unlike apencil line, the tonal value of an ink line remains constant. You can only control the spacing and density o f the hatching. 128 /ARCHITECTURAL GRAP HICS