I'm really trying to apply myself and use the right kind of pens for the right kind of sketches: a brush pen for a quick sketch (bottom left), a thick liner for less hurried ones. The sketch of Benoît Delbecq was done in complete darkness :p (well, I drew the piano and the audience while waiting for the concert to start, so for those I had light.)
Bottom right is a sketch of his technique, putting pieces of wood on the strings to get a very specific sound. Very interesting.
Cărturesti Verona and sala Elvire Popesco - Bucharest, Romania.