What is the term for slowly fading out lighting or sound?

The term for slowly fading out lighting or sound is indeed commonly referred to as "slow fade to." This technique is employed in various performance settings to transition smoothly from one state to another, creating a gradual change that enhances the emotional impact of a scene or moment. A slow fade allows the audience to absorb the action or dialogue, while preparing them for the next phase of the performance.

In contrast, a "snap to" would imply an abrupt or sudden change, which does not provide the same level of emotional transition. "Fast fade to" similarly indicates a quicker change rather than a gradual one. Meanwhile, a "blackout" typically refers to the complete cessation of light or sound, creating an immediate darkness that has a different effect than a slow, gradual diminution. Thus, the terminology of "slow fade to" correctly encapsulates the gradual nature of the transition being described.