Panda Film can help you improve your lighting efficiency. It's that simple. The white surface of this durable, 5.5mil thick film reflects 90% of light omitted while the black surface prevents any light from penetrating through. Panda Film can help you improve your lighting efficiency. It's that simple. The white surface of this durable, 5.5mil thick film reflects 90% of light omitted while the black surface prevents any light from penetrating through. But that's not all! This waterproof, heavy-duty film also helps prevent algae and mold growth on walls.