Adele Wagstaff
As we observe the head or figure we will see gradations of tone moving from light to dark as light touches the surface of our subject. An expressive technique that has great immediacy and can help us to understand tonal relationships within a composition is reductive drawing.
Reductive means to remove or to reduce tone; the process is about the removal and addition of tone from beginning to end. Drawing begins with the placing of tone over the entire surface of the paper. A dusting of willow charcoal may be used, or compressed charcoal will give more dramatic contrasts of light and dark; graphite will allow for many subtleties of tone within a drawing, from very dark to softer, delicate areas of grey.