High-Key Lighting/Low-Key Lighting

In this scene of Harry Potter, high-key lighting is used in the background of King's Cross Station behind the characters Harry and Dumbledore to mimic a heavenly aura; the connotations of the lighting use in this situation is to trick the viewers into thinking that Harry has been killed and has entered the afterlife with his deceased professor. The scene is visually a complete contrast with the rest of the movie which has been completely dark and low-key.

In this scene of 500 Days of Summer, high-key lighting is used to accentuate the main characters and signify their emotions in the moment - due to the lighting they are the central focus of the still with the background of buildings distorted and barely visible. This is used to signify the characters feelings to one another and how they're the only thing that matters in each others perspective. Also, the bright background connotes the characters feelings of euphoria and the sense that they are on the top of the world, signified again by the location of a tall building.

In this scene from Guardians of the Galaxy, low-key lighting is used to underline the menace of Thanos with red and dark colours in the background to represent his destructive path. There is also high-key lighting used which illuminates Ronan's face whilst keeping Thanos in darkness, highlighting how big of a threat that Thanos is compared to Ronan. When a small light shines on Thanos it could represent his good intentions to balance the universe but his twisted means of achieving them.

In this scene from The Exorcist, the main character is in complete darkness whilst facing a shining light that illuminates his silhouette to give him an enigmatic, somewhat sinister atmosphere. The darkness does imply a dark past of the main character but the fact that he is back to it and instead faces the light implies he has put that behind him.