Background Replacement

Yes. Without a green screen the matte is created by rotoscoping rather than keying — hand-drawn frame by frame — which costs more but works on footage that was never shot for it. This is routine for documentary footage, archive material, and anything shot before a background change was planned. The rest of the process, and the light matching that actually sells the shot, is identical.

The existing sky is matted out, a new sky is tracked in to move correctly with the camera, and then — the part that matters — the light in the plate is matched to the new sky. A dramatic sunset sky over a subject lit by flat overcast light will never convince, so colour temperature, contrast and edge light on the foreground are adjusted to match, along with atmospheric haze and grain.

Background replacement swaps the environment behind the subject entirely. Set extension keeps what was actually built or dressed and continues it beyond the edges of the physical set — adding upper floors to a building, extending a corridor, or filling out a crowd space. Set extension usually preserves more of the real lighting, which makes it easier to sell; both are handled here.

Usually one of three things: green spill left in hair and edges, no light match between subject and new background, or a missing contact shadow so the subject floats. All three are integration problems, not matte problems — which is why a clean key alone never produces a convincing shot. Each is treated as its own pass here.