Rotoscoping

Rotoscoping is the frame-by-frame creation of a matte around a subject to separate them from the background. The term comes from the Rotoscope, a device invented by Max Fleischer in 1915 for tracing over live-action footage to create realistic animation. In modern VFX, rotoscoping is used when green screen was not available, when you need to place an effect between foreground and background layers (like fog between an actor and a building), or when you need to apply different color grades to subject and background. It is the most labor-intensive VFX technique—a single second of footage at 24fps requires 24 individually crafted mattes.