Adding grains only to the skin

[Roberto.marinho]

Is there any way to add grain only to specific areas of the image?

For example, I processed a video in Topaz, but the video had a slight impression of rubbery plastic skin, my intention would be to add grain to disguise this bad effect, but I didn't want to add it in areas other than people's skin.
Is there any avisynth filter for this purpose?

[timtape]

Removing grain without also removing some original picture detail is tricky and AFAIK, has only limited success. But reintroducing grain after having taken it away will only add another level of artificiality on top of the "rubbery plastic skin" artificiality. Both in picture and in sound it's so easy and tempting these days to overdo the "restoration". My advice would be go easy on the Topaz in the first place.

[themaster1]

Only on luma, and midtones (skin) with "bump effect" -> g2tex=1):

luma=Grainfactory3(0,3,0,g2tex=1))
mergeluma(luma,1)