I've never been one to fill up sketchbooks. However, when I suffer the occasional 'artist's block' between projects, I'll get out my magazines, or my Michelangelo & Da Vinci books, and do a few drawings from those, just to keep my skill level up. Alternatively, I'll photograph a friend, and draw them ( as is the case with the PORTRAIT OF SIMA, below ).

Above: Portrait of Sima ( preparatory drawing ), 2011

Below: Portrait of Sima ( detail ).

Below: Portrait of Minty

Below: Assorted sketches from books.