The subject of my personal blog today was EDGES. I wonder how many of you think about edges when you sketch? As children, we would draw by using LINES - creating houses, people, etc, with the use of line drawings which described the "edge", or outline of our subject, then we would "colour in" those lines.
However, have you thought about the fact that, figures, for example, do not actually have lines around them? My old tutor used to call the mechanical drawing of a figure's outline "putting wire around the figure". So how do we use line to depict the edges of things which don't actually have edges ...a box may have an edge, but what about an orange? Where, exactly, is the "edge" of an orange? Draw a circle.. but then, it could be flat, like a coaster. What makes us understand that the form continues on beyond the outline?
Do take a look at my blog for some pictures which explain this a little more, and may help you to address the subject with a bit more knowledge and sensitivity.