Blackmagic Forum

Hi can someone tell me how to color correct an alpha matte node,without affecting the background footage in Davinci resolve. I would just like to drag and drop my Still/Grade on the node. I tried reading the manual, but i'm getting lost.. I exported an alpha matte of a 3d model from After effects using a (.EXR file) so i can color correct it to match the background footage i already color corrected in Resolve, I right clicked on the node and created a matte node, after that i'm a bit lost, because this is my first attempt at round tripping for VFX work. How do i proceed from here. Please give me step by step instructions if you can.
Thank you guys oh i'm running davinci resolve 12 Beta

No one can help me?

Simon Dayan wrote:https://www.youtube.com/watch?v=-m4r3H0OjuY

Hey thanks Simon. I did search the Internet and I did watch that video which helped me a lot. But for some reason I still can't find anything on adding a still/grade to a matte node..I basically want to match the Vfx with the background footage that is already corrected in Resolve. Is there anything specific you can point me too? Thanks for taking the time to post the link as well..I appreciated your time

Hi Donnell,
you can add node to youre matte and copy the grade from your background if this is what you meant to do sorry i didn't understand your question try to put your source here and then we can help you on youre source .
take care!

Simon thank you so much I'm going to try that..I'll post back in a bit with my results

Resolve is so powerful framework ....
if you have anti aliasing problem
go to media right click on your Alpha source and choose
change alpha mode ------> premultiplied

Hi Simon, I followed your instructions as well as the one in the video you sent me. When i add the the Still\grade to the node that is connected right after the matte node, i don't see anything happening to the node or grade. I even tried to raise other values like brightness etc.. but it does not affect the node. I also have a Quick question..i rendered out (.Exr) footage with RGB+alpha settings from After Effects and bought them into Resolve. I right clicked and added set matte to the node, but instead of separating the matte it turned the EXR matte node black and white. Is there a setting i need on the front end to be able to pull the alpha from a footage in resolve? In the photo.. i did a separate alpha pass in After Effects without the background, and used that in the screenshot you see above.

hmmm i don't see that change alpha to pre multiplied mode when i right click on my matte source in the media pool

OOOOOKAY!! now i see it thanks simon

try to disconnect the blue wire from the EXT_MATTE and you can see changes ?

i'll try that now...

ok i tried it and it does something..i played with the luminance channel and it got brighter and darker after sliding the curve up or down. But when i add a node after that and play with the luminance channel again to test i don't see any change...see in the second screen shot

great that's good now tell me exactly what you want to do with your black & white alpha?
what are you trying to achive?

ok i'm trying to drag and drop my power grade still to the matte node.. of course when i try that i don't see any differences to the final picture... i basically want to color correct that ship you see in the picture separately from the background by color correcting the alpha matte
Simon, again thank you for trying to assist me with this.

did you put your background pic in the edit on it's own video1
and video 2 is the space ship (above)

hey Simon no i didn't .. i basically thought you can color correct, for example the ship in the same footage by extracting the matte..and grading it.

i could do that ...export the background footage separately from the 3d model..i was trying to save myself time..lol i would love to know the procedure for bringing in VFX work into Davinci resolve to grade from After effects..i use .EXR files to export from Davinci resolve into After effects and back. I'm grading first in Davinci all the background plates, then adding 3d models explosions etc.. in after effects and now i'm trying to bring all of that back into Davinci for Final Grading

well that's why i keep asking you to be sure whats going on .
now you have separate pic you can grade the as you want or copy the grade
and drop your alpha to isolate the area you want .
is this is what you have been looking for?

Yes thats Exactly what i'm trying to do Simon

Great
now you need to check blackmagic fusion 7.7.1 it's a node base VFX better than after effects and it's free
it's time to move on !
take care

..lol you're right Simon it is time to move on.. i'm on a Mac so i have to wait until its released. OK so what you're saying i should do is render 2 separate passes, one with the background footage and the 2nd pass render the premultiplied footage. Pull both .EXR files into Davinci and just drag and drop my power grade to the premultiplied footage to match the Background i already Graded?.. if this is the way then i understand..Thank you simon for you time and patience

yes Henry you got that well !
we all waiting to see a mac version ...soon i hope
take care

Simon Dayan wrote:yes Henry you got that well !
we all waiting to see a mac version ...soon i hope
take care

Yes absolutely Simon ..thank you and take care as well