What material is primarily used to control light spill between areas?

The primary material used to control light spill between areas is a baffle. Baffles are designed to block or absorb stray light, preventing it from spilling into unwanted areas. This is particularly important in theatrical lighting, where controlling the focus and intensity of light can significantly affect the visual composition of a scene. By using baffles, designers can effectively manage where light falls, helping to create distinct scenes and prevent distractions from other elements on stage.

In contrast, absorbers are used to soak up sound or light energy, but they do not specifically direct light, while filters are employed to change the color of the light rather than control its spread. Reflectors, on the other hand, redirect light but do not inherently prevent light from spilling into adjacent areas. Therefore, a baffle is the most suitable choice for managing light spill in a theatrical context.