Kompositing

Compositing, sometimes written as kompositing in some languages, is the process of combining visual elements from separate sources into a single image. In film, television, and digital media, it enables placing live-action footage with computer-generated imagery, mattes, and other elements to create scenes that would be hard or impossible to shoot.

Core techniques include keying, rotoscoping, and mattes. Keying removes a subject from a solid background, usually greenscreen or bluescreen, using an alpha channel or matte. Rotoscoping traces outlines frame by frame to isolate elements when keying is not enough. Matting creates soft edges and preserves transparency where foreground and background blend. Other methods include color correction, edge refinement, motion tracking, plate stabilization, lighting matching, and 3D camera projection.

A typical workflow starts with plate preparation and keying or matte extraction, then layering elements with suitable blend modes and alpha channels. Color grading and lighting adjustments help match the shots, and shadows, reflections, and motion parallax are added for realism. The final composite is rendered and reviewed, with revisions as needed.

Common tools include node- or layer-based software such as Nuke, After Effects, Fusion, Blender, and Natron. Workflows may involve 3D elements, render passes (diffuse, specular, shadow, depth), and color management.

Applications include feature films, television VFX, commercials, and virtual production. Challenges include edge artifacts, color spill, mismatched lighting, motion inconsistencies, and multi-pass integration.