Although most artists use a pattern of light and shade when creating the illusion of three-dimensions, there can be more to the art of portraying this illusion than simply reproducing such a pattern. To give an insight into the complex issues involved, the following discussion focuses on the subtleties and difficulties inherent in applying the Inverse-Square Law with reference to one of Nicolaes Berchem's (1620–83) etchings.
The inverse square law a beginners guide Uploaded by
|Details showing variations of tonal contrast in the three dogs|
| Exaggerated reconstruction of tonal contrasts following the Inverse-Square Law|
|Detail of the foreground dog’s snout|