The shading should follow the shape of the object’s contours, highlighting the volume of its front and side facets. The brightest area of any surface is where it faces the light directly. As the surface turns away from the light source, it gets darker. Other mistakes are:

• “dirty” lights: when your shading won’t read like shading but rather like discoloration on the surface of the object you are drawing.

• dark halftone halo: when you don’t make your dark halftones dark enough, the form will appear flat and you might see what appears like a halo or light glow next to the terminator/shadow line.