(Newser) – A clip making rounds on the web this week offers a fascinating insight into Heath Ledger's preparation for his Oscar-winning turn as the Joker in 2008 film The Dark Night. In the clip, taken from German documentary Too Young to Die, Ledger's father leafs through the actor's journal, showing notes, clippings, and drawings he used as inspiration for the performance, reports News. "He pretty well locked himself up in a hotel room for weeks," says father Kim. "He immersed himself in the upcoming character on every level." Written on one page: "BYE BYE."