Isolated layer capturing reflections and light bounces — composited over glass, water, or metal surfaces. Gives you precise control over reflectivity without reshoots.
You're shooting a scene with a glass door, an illuminated interior behind it, and actor action in front. The reflection needs to be precisely visible — but not so dominant that it overpowers the performance. This is where you reach for the Reflection Pass: a separate shot or a dedicated VFX layer where only the reflections are captured or generated in isolation. In compositing, you then overlay this pass onto your main shot and control its opacity, blend mode, and position pixel-perfectly — without risking a single reshoot.
The practical execution usually occurs in two scenarios. On-Set Capture: You shoot the same camera position a second time, but without talent — just the reflections visible behind the reflective surface. Or you print the scene behind it separately through a clear glass plate. This works elegantly in the studio with controlled lighting; on location, it's a test of patience. VFX Generated: The compositor reconstructs the reflections — they mirror elements, adjust them for sharpness and opacity, and adapt them to the surface curvature. This costs time in editing but saves you shooting days on set.
The key advantage lies in post-production control. Reflectivity, saturation, blur, specularity — everything remains modifiable. You only realize during the first cut that the reflection appears too dominant? Change the blend mode to Screen instead of Add, set opacity to 45 percent — done. For water surfaces, for instance, the Reflection Pass works similarly: a separate layer for the water surface reflections (sky, shoreline, ships) that you can control independently of the water texture. This is standard, especially for CGI water — first comes the geometry with bump/normal, then the Reflection Pass over it.
Pro Tip: If you're on set and have reflections in the frame, take at least one clean plate without the reflective surface and a second shot that captures the surface itself (with all its imperfections, scratches, dirt) in isolation. This allows the compositor to correctly insert the Reflection Pass under the surface texture later without it looking fake. For mirrors, it's even more critical: the angle of the Reflection Pass must mathematically align with the camera — here, you pay with millimeter precision, not artistic feeling.