What is a key characteristic of incidental music in film?

Incidental music in film serves primarily to enhance the mood of a scene, creating an emotional backdrop that supports the narrative without drawing attention away from the dialogue or action. This type of music can subtly influence the audience's feelings and responses to what they are seeing on screen, making it an integral part of the storytelling process.

While incidental music can sometimes be instrumental, it is not a strict requirement for it to be labeled as such. The key purpose remains how it contributes to the atmosphere, supporting the film’s emotional landscape. Other options, such as the need for lyrics or being excessively loud, do not align with the function of incidental music, which aims to complement rather than dominate the scene.