Here’s my 1.5 cents:
AE can do wonders with the built in grain tools. Andrew Kramer (homesite: http://www.videocopilot.net) has some great presets available, one of which is a grain addition via a noise filter.
AE’s tools work very very well, but the grain tools can be EXTREMELY time consuming to render. Kramer’s tool *I BELIEVE* uses a fractal noise filter (very fast) and randomizes the seed… again, if I had to guess. I have the preset, though I have not used it yet. In tests it looked very good and much faster than AE’s built in tools.
I would recommend trying a trial film out of your project as Dave suggested above. Say a test reel of a few minutes of film. Most of the time when you are adding grain you are simulating film for another medium (video) or matching grain for composited objects that you want to look like they belong. If you film out everything to 35mm, you get the real (pun intended) deal. IF you’re unhappy with the results of the test, THEN you can drive yourself crazy trying to add in some grain prior to film out. I will warn you though, trying to “add” grain and then sending to film which has its own grain, may be more difficult to match and look natural than you think….
—
Austin Reeves
AR&C
Production & Post Production Services