As before, Ms Riefenstahl's filming and editing techniques both broke new ground, and many shots that now seem commonplace had never been seen before.

ECONOMIST: Leni Riefenstahl: Hand-held history | The

As on the Philosopher's Stone there is still no information on the filming locations or production techniques employed in making the movie.

BBC: Dobby the house-elf

Like pre-existing blue-screen techniques it involves filming a scene against an aquamarine blue-coloured background.

BBC: Blue and green-screen effects pioneer Petro Vlahos dies