On a green screen set, the light on the talent and the light in the background are two separate problems, and someone has to make them agree later. On an LED volume, much of that agreement is built in. The wall is a large light source that shows the scene, so the colours of a sunset fall on the actor's face and the blue of a night street reflects in a car door.
What the wall does well
Soft, wrapping light. A wall is a big source, so the light is gentle and even.
Matching colour. Light from the sky, the neon sign or the fire comes from where it appears in the picture.
Believable reflections. Glass, metal, wet surfaces and eyes show the environment without added effects.
What it does not do
Hard light. Direct sun and strong shadows need a real fixture. A wall cannot be bright and tight enough.
Overhead light. A wall behind and beside the subject does not light them from above. A ceiling of LED panels or soft lights covers that.
Very bright highlights. A wall is bright but not as bright as the sun. A fixture adds the sparkle.
Where stage lights come in
Key lights with a clear direction, a top light for the shoulders and hair, and a rim light to separate the talent from the background. Place them to agree with the sun or lamp in the scene, so the shadow on the floor points the same way as the shadow in the picture.
Keep stage light off the wall
Any light that spills onto the screen lifts the blacks and washes out the image. Flags, barn doors and distance keep fixtures where they belong. Dark scenes are the most sensitive.
The floor
The floor carries reflections and bounce light too. A matching physical floor, or a wall section laid under the talent, keeps the join between set and background from standing out.
Plan it with the gaffer
Share the environments before the shoot so lighting is planned for each. Treat the wall as one fixture in the lighting plan, not as a replacement for it.
Planning a look? Send a reference to wlab@wlab.tech.
Cover image: an illustration generated for this article, not a photograph of a WLAB shoot.
