with these little cg characters to the point where you really had to feel harry's emotional distress dolbythe audience to shed a tear. it's quite a challenge, bus i think we managed to pull that off. that was quite a difficult thing, but, very rewarding as well. >> larry: but for every rewarding visual challenge there is some effects that burke says had fallen flat. >> some things, you're pleased with other things that never quite were at good as you hoped, and i think for me, if i'm completely honest it would probably be in the fifth film didn't quite hit the mark unfortunately. we weren't really quite sure how believable he was at the end of date. that was very difficult, to be honest, and you know, can't win them all. so -- >> larry: one of the most important transitions tim and his team have done, turning ralph fiennes into lord voldemort. seen for the first time publicly, we're able to show you how it was done. >> we mastered the technique over the years and basically ralph fiennes wears makeup, prosthetic makeup and matrix, the cover the area of his face that we have to replace with