Help! RED to NUKE VFX and back for completed feature

[Alexander DJ Martin]

Hi - 5 years ago I shot a feature on RED 1. You can find a teaser at facebook.com/thedevilwentdown - Lots of problems since and we ran out of money but finally the edit is locked in AVID. and we are onlining in AVID before sending to a grader as DPX. I have a nuke guy who has done lots of VFX work for us but we're having trouble matching his VFX with the RAW RED footage. I am a total beginner at this and need a simple workflow to give to the VFX guy.

The RED files seem to have Red Gamma embedded but we are grading in RedLOG exported to DPX.

What is the best way to get REDLog rushes into Nuke and back as DPX that will match the original? should I export from RedCineX as exr and if so how do I get the RedLog colour space?

Any help/advice would be great!

Alex

 

[PatrickFaith]

hmm, looks like some fun performances worked in there on your clip. If you've been doing the film for that long, my bet is you have around 7 major problems, probably need to bring in a vfx supervisor for a week to cleanup things. Anything i say on how to do this, theres a bunch of ways to mess it up. For example theres a difference between data space and video space when your write log formats out of nuke - which i had messed up in my film when it was delivered to grading.

 

[Björn Benckert]

IF that is your work flow the nuke guy should have used redlogfilm as input and then a a log2lin lut and corresponding reverse lut after he applied the vfx. Doing so he can basically deliver DPX files identical to the rest of the material but with his effects applied to them.

Now I guess he opened the files with redgamma1,2 or 3 or 4and then did all his work and exported. So shortest way home is to apply a redgamma 1,2,3 or 4 (depending what he used on the way in) to redlogfilm lut and then grade.

But there is a risk when doing these color transformation that clipping and clamping may degrade the footage. So if it was not done with caution for clipping/clamping on the way in then he might have to adjust for that and rerender his effect shots whithout clipping.


So first find out what he did on the way into nuke. what redgamma he used. Then get the right lut to flip it back. And hopefully thats all there is to it.

 

[Alexander DJ Martin]

Hi Bjorn, thanks for your response. Forgive me for not knowing even the basics, but when you say 'should have used redlogfilm as input' do you mean that is a setting in nuke? Should he be importing the actual RED files or should we be converting them to something first?

Thanks!