Film grain
Also called: Super 8 grain, emulsion grain, film noise, celluloid grain
Film grain is the organic texture of silver crystals and dye clouds in the emulsion. See why Super 8 grain is coarse and how to build it with Super8 Film Lab.
WHAT CAUSES IT
Film grain is the random texture produced by the light-sensitive particles in a photographic emulsion. Black and white film holds microscopic silver halide crystals, and when light strikes a crystal, development turns it into a dark speck of metallic silver. Color film layers hold the same crystals, but after development the silver is bleached away and replaced by dye clouds that formed around each developed crystal, so the visible grain is a cloud of dye, not a metal particle. The crystals differ in size and are scattered at random, so the density of the image varies from point to point even in a uniformly lit area. Faster films use larger crystals to gather more light, which gives coarser grain, and underexposure pushed in development emphasizes it. The grain pattern is independent from frame to frame, because each frame is a new exposure. A Super 8 frame measures roughly 5.7 by 4.2 millimeters, and projecting it to a large screen magnifies the grain more than any larger format would. Grain is most visible in midtones and shadows.
WHAT IT LOOKS LIKE
A lively, shimmering texture over the whole picture that changes every frame, often described as boiling at 18 frames per second. At close view it looks like clumps of soft, irregular specks, larger and more visible in flat areas such as sky, skin, and walls. The grain shifts a little with color, producing faint chromatic noise in color stocks, while black and white stock shows a neutral grain. Higher speed stocks show a heavier, creamier texture, and fine detail dissolves into it. Highlights look cleaner, and underexposed shadows can look gritty and low in contrast.
WHERE YOU SEE IT
Home movies on Super 8, 8mm, and 16mm film, documentaries from the film era, low budget features shot on reversal stock, and every modern production that adds grain to soften digital video. Super 8 grain is the signature of the home movie look, associated with family footage from the 1960s to the 1980s. Editors add it as a final texture over digital footage to unify graphics and effects, and to hide banding or compression noise.
RECREATE IT
SUPER8 FILM LAB
CONTROLS GRAIN, EXPOSURE FLICKER, BLOOM
GRAIN is the main control: raise it until the texture is visible in flat areas at normal playback, then back off a little, since grain that is obvious on a still often looks too heavy in motion. EXPOSURE FLICKER adds the frame to frame brightness variation that accompanies it in real film. BLOOM is optional; use it for a softer, vintage glow. Keep dirt controls out of this pass, since they do not combine well with the other effects.
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HOW TO MAKE IT IN AFTER EFFECTS
1. Open the footage in SUPER8 FILM LAB, which is a standalone Windows application, not an After Effects plugin. 2. Raise GRAIN until the texture reads in the flat areas of the picture, and add a little EXPOSURE FLICKER. 3. Export the grain pass as its own clip, since the app writes grain, bloom, halation and matte passes as separate files. 4. Import the exported clips into After Effects together with your original footage. 5. Place the grain clip above the footage and follow the blend instruction that comes with the export. If you need a starting point, Overlay or Soft Light are common choices for a grain layer. 6. Lower the layer opacity until the grain supports the picture without hiding it. 7. If you want to control grain separately from the rest, keep it on its own layer, so you can change its strength after the edit is locked. 8. Match the composition frame rate to your project, and render a short sample to check that the grain moves every frame. 9. Place any titles above the grain layer if you want them clean.
QUESTIONS
- Why is Super 8 grain so coarse?
- The frame is very small, about 5.7 by 4.2 millimeters, so projecting it to a screen enlarges every grain particle far more than 16mm or 35mm. Home movie stocks were also fast and cheap, with relatively large crystals. That combination is why even a well exposed Super 8 shot looks grainier than a studio feature.
- Is film grain the same as digital noise?
- No. Digital sensor noise is a fixed grid of pixels reading random values, and it is mostly color speckle at pixel scale. Film grain is a random arrangement of particles of varying size with no grid, so it looks softer and more organic.
- Should grain change every frame?
- Yes. Each film frame is a fresh exposure, so its grain pattern is unrelated to the neighboring frame. A frozen grain overlay looks like dirt on the glass. Randomized grain gives the lively boil of real film. If you animate grain by hand, change the seed every frame, or let the tool do it for you.
- Does grain make footage look more real?
- It adds texture that the eye associates with film, and it can hide banding and compression noise. It does not fix lighting, movement, or lens issues, so it works best on top of a convincing picture. Used lightly, it is a finishing texture. Used heavily, it becomes the main look of the shot.