INTRODUCTION 29 



tive brightness of objects of different colors.) All surfaces so 

 directed as to receive and reflect most of this light to the ob- 

 server's eye will be brightest (unshaded, or having " high 

 lights 77 ); those directed away from the light will be darkest 

 (shaded, or in shadow) ; while surfaces having an intermediate 

 direction will be shaded less or more according as they approach 

 one or other of the above extremes. 



A plane surface will have uniform light or shading. Rounded 

 surfaces will have graduated shading ; areas separated by sharp 

 edges will have abrupt differences of shading, the contrast being 

 greater the smaller the angle between the adjacent areas, or, in 

 other words, the greater the difference in their direction. In 

 rounded objects the highest light and the deepest shade are sit- 

 uated close to, but not at, the edge of the outline. All the shading 

 should be kept right in relation to the deepest shadow. 



The student should examine book-illustrations and observe 

 how shading is represented, (a) Some degree of depth may be 

 given in a mere outline drawing by making the lines on the lower 

 right side of the objects heaviest, (b) Plain parallel lines are 

 used for shading in " line" drawings. The depth of shading is 

 varied by the heaviness of the lines, their distance apart, and by 

 " cross-hatching" or putting additional sets of shade-lines over 

 the first at very acute angles of crossing. 1 (c) The pencil may 

 be held obliquely and rubbed most on the parts to be shaded, 

 giving a photographic effect, (d) Some of the lead of the pencil 

 may be scraped off with a knife and applied to the drawing-paper 

 by means of a paper stump, giving a means of rapid working, but 

 one that is apt to give a smudgy effect, (e) Wash-drawings are 

 shaded either by repeating the wash or by using a stronger wash 

 on the shaded parts. (/) A softer pencil may be used for the 

 deeper shading. Finally, it is well to " pick out" the high lights 

 with a soft eraser, (g) Dots may be used instead of lines, as in 

 stippled drawings, Ross-board drawings, and half-tone illus- 

 trations. 



Colors may be utilized to differentiate structures, e.g., red 

 for arteries, blue for veins, brown for muscles, green or orange 

 (or plain black) for nerves. Good crayons are useful here. Big- 

 gins 's inks of various colors may be used in pen work. Washes 

 are very effective also. As a rule, all color should be used very 

 sparingly, and so should shading. 



1 Sometimes the shading lines are curved in conformity to curvatures of the 

 surfaces depicted, as may be seen in old wood-prints, steel engravings, and 

 mechanical drawings. 



