col legno tratto
techniqueskol LEN-yo TRAH-to
A string technique in which the bow is drawn across the strings using the wood of the bow rather than the hair
While col legno battuto (bouncing the wood on the strings) is more common, col legno tratto asks the player to draw the wooden stick along the string, producing a ghostly, scratching whisper. The sound is barely audible and profoundly unsettling, used for atmospheric and supernatural effects. Penderecki and other avant-garde composers employed it extensively. String players are often reluctant to perform the technique, as it can damage expensive bows.
Professional orchestral players sometimes keep a cheaper spare bow for col legno passages to avoid damaging their primary bow.