fadein
Fadein, also written as fade-in, is a gradual increase in visibility of an image, scene, sound, or UI element. In film and video, a fade-in typically starts with a black frame and gradually reveals the image as the opacity rises from zero to full, often used to open a sequence or after a fade-out to transition between scenes. The process can be linear or eased to create a smoother or more dramatic start. In audio, a fade-in increases volume from silence to the intended level, commonly used at the start of a track or after a pause; the onset can follow linear, logarithmic, or other curves to shape perception. In user interfaces and web design, fade-ins reveal content by increasing an element’s opacity, often with subtle movement or scaling; CSS and animation libraries provide tools to implement these effects. Durations typically range from a few tenths of a second to several seconds, chosen to match pacing and readability.
Fade-ins are often paired with fade-outs or crossfades to create smooth transitions. They are a foundational