I analyzed Harry Potter and the Chamber of Secrets. Overall, the lighting in the movie starts out bright and then progressively becomes darker as the story unfolds. This serves the purpose of creating drama as the story becomes more and more dire. By the end of the movie, the lighting is noticeably brighter again, most likely to symbolize that the evil has gone and that everyone can be cheery again.
There is one scene in particular towards the end of the movie where the lighting and shadowing are most noticeable. Harry and Dumbledore are discussing Harry's triumph in the Chamber of Secrets when Lucius Malfoy enters. The lighting on Malfoy's face uses a unique technique that I hadn't seen before, where all of Malfoy's face is cast in shadow except for a horizontal line of light across his eyes. During this time when his face is shadowed, the audience focuses on the gaze of Malfoy as he mockingly talks about how he only has the welfare of the students in mind. Later in the scene, we see his eyes turn from powerful to shameful as he realizes that his plan of assisting Voldemort has been found out.
This use of shadow is balanced with the bright faces of both Dumbledore and Harry, brought on by above-eye level lighting. I believe this contrast serves to suggest the classic contrast between good and evil. I believe this technique is being used in much the same way that below-eye-level lighting would be used: to make Malfoy appear evil and malevolent or frightening. This lighting is important because it serves to tell us as the audience that this character will appear again and may bring harm to the main character.