Which lighting technique focuses a beam directly on an actor's face?

The technique that focuses a beam directly on an actor's face is known as key light. This lighting method is crucial in establishing the primary illumination on a subject and is often used to highlight the actor's facial features and expressions. By directing light straight at the actor, the key light creates a sense of depth and dimensionality, which helps to engage the audience and draw their attention to the performance.

In contrast, flat front light aims to provide even illumination across the actor's face but may not specifically highlight features or create distinct shadows. Backlighting involves positioning lights behind the actor, adding depth to the scene or creating silhouettes, while side lighting also serves to shape and add dimension but from the lateral aspect rather than directly capturing the face. Each of these methods plays a unique role in stage lighting, but key light is specifically significant for focusing directly on an actor's facial features.