fade-in

a moviemaking or broadcasting technique in which the sound and image is made to appear gradually

A fade-in is a technique used in film and video production where both the image and sound gradually appear on the screen from a completely dark or silent state. This effect starts with a blank screen and silent audio, then slowly introduces the visual and audio elements, allowing the scene to emerge smoothly. A fade-in helps to create a gentle transition from darkness to light and from silence to sound, setting the tone or mood as the scene begins.