Grain

Grain [Grn] is the legacy Fusion Film Nodes grain tool. Resolve 21 retains it so older compositions continue to load and render. Blackmagic recommends the newer Film Grain [FGr] for almost every new film-emulation task; these are separate nodes with different algorithms and inspector controls.

Grain processes standard 2D image pixels. Orange Input accepts footage, graphics or a finished composite. Optional blue Effect Mask restricts the processed contribution; Output returns ordinary 2D RGBA. The tool does not emit particles, material streams or a standalone grain mask.

Power scales the apparent strength of grain. The archived 5.0 in the screenshot is a demonstration setting, not a safe default for all sources. Check the effect at actual delivery resolution and 24 fps playback. Per-channel strength also depends on Red, Green and Blue Difference.

Grain Size controls particle scale, Softness controls edge fuzziness, Spacing adjusts density or separation and Aspect ratio controls the particle shape. None of these four controls is just another global intensity slider; matching real imagery requires several independent comparisons.

RGB Difference provides a global difference in the grain applied to each color channel. Spread is a distinct tonal-response system: it modulates grain across the input brightness range of each RGB component. On a fixed test plate, compare Difference first, then change the corresponding Spread spline.

The saved Spread screenshot shows Red/Green/Blue enable checkboxes, spline editor and In/Out fields. These channel curves affect the grain response rather than the color grade of the original pixels; Spread is not an ordinary Color Curves node or an alternate texture output.

A flat Spread yields a more uniform tonal grain response. A broad bell-shaped curve can favor midtones over the deepest blacks and brightest highlights. Tune the curve to a reference source and inspect each channel individually; no specific curve from this article should be assumed to be a calibrated preset.

Alpha-Multiply factors the source image alpha into grain, helping keep fully transparent Text+, keyed-object or PNG regions free of extraneous noise. However straight/premultiplied formats and partially transparent edges need a real Viewer check after Merge over both black and white backgrounds.

For full-frame grain, use it near the end of the grade/composite. For spatially localized grain, connect RectangleMask or Bitmap.Mask to blue EffectMask while retaining the image in orange Input. A mask stream never substitutes for the primary source image.

Matching grain to live camera material benefits from A/B on equal-resolution regions. Compare Power, Size and Spread on fairly uniform patches; treat CGI, AI graphics and other insertions in a consistent context with their surrounding footage.

Grain is temporal texture. A perfect paused frame can turn into unpleasant shimmer or blockiness after H.264/H.265/AV1 compression. Review several seconds of motion, small details and actual output bitrate. The presence of a Grain node does not guarantee removal of image banding.

The original grain-controls.png and grain-spread.png are preserved. They establish the visible Inspector control inventory, not native scripting port IDs, measured pixel results or exact response curves. The interactive graph lessons validate semantic image/mask typing only; actual execution on Resolve 21/21.1 remains pending.