I often work on black (paper or gesso), which is fun, and easy to the get the highlights right, but the shadows are difficult. Working on white has the opposite problem, the shadows are easy but the highlights are difficult.
I got this bright idea: I would do my pencil drawing like usual and not worry the highlights. When I was finished I cut a piece of tracing paper and taped it over the drawing. Then I penciled in the highlights, but in reverse- like a negative. I should have taken more care cutting the tracing paper because it made it more difficult to get the alignment right when I scanned both drawings.
Over the original pencil 'pos