Grain Match

nahcra · 11:55 AM

Hi all I have been working on a VFX shot on a feature some rig removal shot as i used neat video to degrain the footage and creat patch now the problem is that thegrain is not matching up I tried all the trick up my sleeve used regrain tool in nuke match grain in AE created grain map all the things i could think of but the grain on this shots are really crazy.

Did a first pass on these shot but the DP was not happy with the grain as the VFX footage grain did not match the original plate how to match a grain perfectly...........

any help would be G8

raksol · February 3rd, 2010, 12:18 PM

I would suggest the ReGrain node that comes with Furnace core, (included in NukeX) IF you have it. It's really nice.

Other than that, just try to match it in the separate rgb channels with the grain-node in nuke would be my best tip!

Good luck!

beaker · February 4th, 2010, 02:30 AM

are you degraining/regraining the entire shot or just the patches? You should be doing the latter.

nahcra · February 4th, 2010, 02:32 AM

hey raksol thanks for the reply..i did that stuff but not working ....MY DP is one hell of a shit,,,,....when the liquid cc is done on DI ..the patch looks the same like not done anything,,,

hybrias · February 4th, 2010, 10:46 AM

could this be a case of log/lin?

from what i understand. nuke is pure linear auto conversaion. so this may not be the case but when i've done some comp work/patching when i comped in log it produced some odd results for grain matching.

zistambus · February 18th, 2010, 10:41 PM

Match the grain looking through your linear value in Nuke... and compare the grains of the final node with the input's...check all channels Red,green blue, match the size,gain,softness,etc...exactly... as original... and then check the LOG sources of ur input and final render....again it should match...now take ur shot to the colorist and check it.

Vinteg · February 18th, 2010, 11:08 PM

Another thing to be mindful of that grain is more visible in the darks than the lights. Use the ranges tab in the grain to make sure they match or combine the alpha with an inverted luma key.

Also if you are using a fatty blur for your patches, the soft gradient areas of your alpha will be grained less creating a grain halo. Increasing the whitepoint in you alpha and graining the patches after you merge the patches on top can fix this.