4 Replies Latest reply on Feb 9, 2013 5:46 PM by Todd_Kopriva

    AE CS6 - 3D Compositing and Color Correction workflow

    Simon Luchini

      AE CS6 - 3D Compositing and Color Correction workflow

       

      Hello everybody,

      I have some questions about work flow in AE concerning compositing and Color Correction. I saw many tuts about (f.e. Lynda.com Premiere Pro Color Correction and Enhancement... and tuts by Andrew Davis here in creative.cow).

      Essentially, he have this CC work flow:

       

      GRADING (primary and secondary)

      Adjusting Tonality (Brightness and Contrast)

      Adjusting Colors (White balance and fix color dominance)

       

      MATCHING

      Conforming colors of different clip shoted with different camera and lighting set up.

       

      ENANCHING LOOK

      Giving to all clips a unique "look"

       

       

      But what does it  happen if we have NOT just some clips but ALSO a 3D object (rendered in a 3d sw or, actually also a 3d object inserted by 3D Element by videocopilot)

      or/and

      a keyed clip from a green screen shot?

       

      How does this footage (3d object and green screen keyed shot) transform

      the aforementioned work flow?

      We have to consider that this footage (3d object and green screen keyed shot) must to be pre-multiplied to make a right compositing but when you make CC it must be again "straight"... (NOT pre-multiplied)

       

      Is really hard also understand how dale this work flow between AE and Pre Pro if you want to make CC in Pre Pro after compositing in AE.

       

      I try to present a work flow for this (very common) situation:

       

      I have a landscape clip as a background

       

      a keyed clip (pre-multiplied) with a Character watching sky

       

      and a 3d (pre-multiplied) object U.F.O. on sky.

       

      When I have done compositing, how make I a right CC of all footage if I have two clip (3d object and green screen keyed shot) still  pre-multiplied?

       

      I think, but I'm not sure, that should be a good idea to send to Pre Pro a composited Comp with separate layers (by dynamic links)  to have  all single separate layers (Background, 3d object and green screen keyed shot.. but also the Color Warping...!). Than, in Pre Pro you should make a CC (Grading)  just for a BG and than try to Match (Matching) this color corrected BG with 3d obj and keyed shoot. But we have a problem at this point cause our 3d object and green screen keyed shot are still pre-multiplied, and before make matching we have to re- multiplied theme, but how? And if we re pre-multiplied them, compositing will be also right?

      Or maybe, before exporting comp from AE to Pre Pro, he have to create both layers for 3d object and green screen keyed shot, one pre-multiplied and one "Stright"? But, again, how to combine them to have a right compositing and a a right CC?

       

      Anybody can help me to understand or maybe suggest any tuts to dale this common issue in AE- Pre Pro?

      Many, many thanks!

        • 1. Re: AE CS6 - 3D Compositing and Color Correction workflow
          Mylenium Most Valuable Participant

          What has all your premultiplied vs. multiplied have to do with color correction? Your whole workflow sounds awful. You simply combine everything in one program and render it out as a flat clip and that is it. Nobody would render elements with Alpha in AE and color correct them just so he can then assemble them in Premiere over his footage there. Makes absolutely no sense. Do whatever you must in Premiere, move over to AE and use it there, including your final color correction for your 3D elements, rtender it out, import the result in Premiere and replace the clip.

           

          Mylenium

          • 2. Re: AE CS6 - 3D Compositing and Color Correction workflow
            Simon Luchini Level 1

            Hi Millenium, if you don't know what "What has all your premultiplied vs. multiplied have to do with color correction", this discussion can't to go forward, not with you.

            And try also to read correctly what people write. There are three type of clip to composite in my example: Keyed clip , 3d Obj  and 3d obj by 3DE videocopilot. All these clip have a different ways to build alpha and maybe, 3D Element plugin doesn,t use alpha...

            And please, google what is the different beetween Straight and pre multi footage in Color Correction.

            Bye!

            • 3. Re: AE CS6 - 3D Compositing and Color Correction workflow
              Dave LaRonde Level 6

              The only time you need to worry about premultiplied and straight is when you render a file in AE that contains an alpha channel.

               

              You're doing color correction.  You don't NEED to worry about alpha channels.  Alpha channels don't apply to your situation.

              • 4. Re: AE CS6 - 3D Compositing and Color Correction workflow
                Todd_Kopriva Level 8

                Dave is correct. (And so is Mylenium. No need to be rude, when he was jsut trying to explain that you were introducing unnecessary complexity.)

                 

                The color matting is removed to interpret the alpha channel when you import the footage. After that, any color correction that you do to a layer based ont hat footage item doesn't have anything to do with whether the channels were straight or premultiplied for the source item.

                 

                You color-correct your individual items to amke them match as part of the compositing process in After Effects. Then, if you want to do a color grade of the shot in Premiere Pro along with other shots, you'd be working on the single rendered/flattened composite, so the details of the original elements that went into the composite are irrelevant.