Matte

A matte is a mask used specifically in compositing to define the opaque and transparent regions of a foreground element, allowing it to be combined with a background. The term derives from optical printing: a matte was originally a piece of opaque material placed between film and a printer light, blocking exposure of some regions while letting light through others. In digital compositing, matte refers to the alpha-channel-equivalent layer that says 'this part of the foreground exists, this part is transparent.' Mattes are produced by various techniques: green/blue screen chroma keying generates a matte automatically from color information; difference matting subtracts a clean plate from a shot with subject to derive the matte; rotoscoping manually draws frame-by-frame mattes for situations where keys don't work (subjects in front of complex backgrounds, smoke, hair); difference keying combines two takes (one with subject, one without); luma keying isolates based on brightness; and AI-based matting (Adobe Sensei, Resolve Magic Mask) increasingly automates traditional roto. Soft mattes (anti-aliased edges with partial transparency) are essential for natural compositing — hard-edged mattes look pasted. Matte refinement workflows include edge erosion, motion blur application, despill (reducing green/blue cast on the foreground subject's edges), and edge defringing. Reference: Brinkmann's 'The Art and Science of Digital Compositing' covers matte generation theory comprehensively.