File:Postprocess controller film grain.jpg

Left 4 Dead is more frightening in a dark and shadowy environment. We found that applying a film grain technique heightened this feeling, both in helping to make the cinematic experience as gritty and authentic as possible, and in how effectively it implies a greater detail to the surrounding darkness than is actually there. Thanks to playtesting, we also found that if we applied the film grain effect uniformly, people got tired of it fast. So we tweaked the technique. Consequently, in very dark areas with a lot of shadows, there's a lot of film grain visible. But the brighter an area gets, the more the grain fades into the background, and disappears entirely in very bright areas.