What is the main source of lighting referred to in a scene?

The main source of lighting in a scene is referred to as key light. This term is used in theatrical and cinematic lighting to denote the primary light source that illuminates the subject, creating the desired mood and highlighting important features. The key light is strategically positioned to set the tone for the scene, influencing how viewers perceive depth, texture, and emotion.

In contrast, flat light typically refers to lighting that diminishes shadows, leading to a more uniform exposure on the subject, which is often not the intended effect for dramatic scenes. Ambient light provides a general illumination in the environment without necessarily spotlighting specific details or subjects. Fill light serves to soften or reduce shadows produced by the key light but is secondary to its impact. All these other types of lighting play supportive roles, but none establish the primary focus as effectively as key light.