 Ingres was self @-@ critical and consumed by self @-@ doubt . He often took months to complete a portrait , leaving large periods of inactivity between <unk> . With Bertin , he <unk> in finding a pose to best convey both the man 's restless energy and his age . At least seven studies survive , three are signed and dated . Ingres was a master draftsman and the sketches , if not fully realised , are highly regarded in their own right . The sketches are exemplary in their handling of line and form , and similar in size . 
