There are different types of grain nodes in nuke, but the problem is, while they may accuratly emulate specific types of filmgrain, they make your image – to put it mildly – really ugly.
This is why I decided to create a “beautiful” grain gizmo. The key thing in my opinion is, that noise shouldn’t modify chroma, but luminance. I exposed knobs to control intensity and grain size (just a blur essentially). There is also a threshold to keep bright areas clean and another to produce extra noise in dark areas. No voodoo involved, but maybe you find it useful anyway.Download beautiful grain gizmo