A friend of mine mentioned that in art school in Korea, you would probably take about a year just to master this aspect of drawing balls. She's been practicing drawing balls with her Korean teacher and I have to say, her ball was really fantastic and so much better than my rustic looking eggs (above).
Anyways.. the project this week was to place some eggs on a white sheet of paper and observe the shadows and highlights in relation to the direction of the light. It would have made things easier if I'd used a lamp to emphasise the direction of the light, but as it was, the light was coming from the window and hitting the eggs in a couple of different places. The shading was supposed to be done with cross hatching. I'd like to do more spherical tonal practice, just to work on the technical aspect of the shading to understand it and to get it right.
Below are some other tonal practice drawings I did a few years ago from Bert Dodson's "Keys to Drawing" book, using knowledge of the tonal categories