Expressions are pretty new to me, and i've been doing beauty shots for a massive amount of clips using the default plugin "remove grain" for skin smoothing in After Effects CS6.0. To my knowledge, remove grain has no source or layer referencing like many other plugins for degraining. The remove grain in the comp is on an adjustment layer with a track matte of luma invert to a black and white matte above it (eg. videocopilot's beauty tutorial). Although the plugin does a great job, we need to get consistent levels of smoothing and was wondering if there was a way to use expressions to point the remove grain's source frame to a specific source/layer (preferably a layer in the same comp). This would be similar to a noise sample (in other plugins) to use for all clips. Any help would be greatly appreciated. Thanks for your time!
There is no way to add the functionality of sampling a different layer than the one the Remove Grain effect is applied to. That would require a re-write of the effect.
That said, you could pre-compose all of your footage layers and add your noise sample image to the pre-comps as the first frame (Frame 0) only. Now when you apply the Remove Grain effect to each pre-comp it will be sampling the noise sample frame by default (Frame 0).