A light grain pass over the final composite is the most reliable 'make it look intentional' move — it unifies layers and hides banding

Adding a subtle noise/grain pass as the last step in the image pipeline — after all layers are composited — is a standard production technique with multiple benefits: it unifies disparate layers that might otherwise appear disconnected, it hides banding and compression artifacts, and it gives the image a film/analog texture that reads as intentional rather than digital-sterile. The critical design rule is ‘grain is seasoning, not a layer’: it should be subtle enough that removing it would make the image slightly worse without the viewer knowing why. Heavy grain dominates the texture hierarchy and defeats the underlying composition.

Examples

Hydra: .add(src(o1).mult(solid(0,0,0,0)),0.04) where o1 = noise(400,0).out(o1) high-frequency noise; or GLSL: col += (hash(uv+u_time*0.1)-0.5)*0.03 on the final color.

Assessment

Explain three distinct benefits that a final grain pass provides to a composited image. Then state the design rule for grain intensity and explain what happens visually if the grain is applied too heavily.