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Activity Forums Adobe After Effects Preserving an Alpha Channel in an Animation

  • Preserving an Alpha Channel in an Animation

    Posted by Ron Moore on March 21, 2013 at 4:08 am

    I’ve rendered a logo animation with an alpha channel in Cinema 4D and opened it up in After Effects with the intention of adding a background in Premiere Pro, with the logos with alpha on top and b.g. showing through, and saving for a web video presentation but I can’t seem to preserve the alpha when I end up in Premiere. Should I render this part of the video in After Effects with the intended background composited and then take it over into Premiere, or is there a way to preserve the alpha (or key out the black b.g. in Premiere) and then add the final b.g.?

    Joseph W. bourke replied 13 years, 1 month ago 3 Members · 6 Replies
  • 6 Replies
  • John Cuevas

    March 21, 2013 at 1:17 pm

    Do you have transparency now(click the checkerboard under the comp window)?

    If you do then you need to render out file that supports transparency, like QT_Animation & specify that you want an alpha channel to be exported. For a QT, send your file to the render queue, and change the click on “Lossless”, select Quicktime(change the codec to animation) and change your video output > Channels to RGB + Alpha.

    Johnny Cuevas, Editor
    Thinkck.com

    “I have not failed 700 times. I have succeeded in proving that those 700 ways will not work. When I have eliminated the ways that will not work, I will find the way that will work.”
    —THOMAS EDISON on inventing the light bulb.

  • Joseph W. bourke

    March 21, 2013 at 1:22 pm

    If C4D can output a Quicktime movie in Animation, with Millions of Colors+ setting, you have no need to go into After Effects. Just make sure when you make the settings that Color and Alpha are checked, or you’ll end up with no Alpha channel.

    Interestingly enough,in the days when I had to render 3D animations to go to air and key out through a switcher, there was an output setting called Superblack, which set the black levels at 0, not the traditional 7.5 IRE of broadcast (NTSC anyway). This allow a switcher to “see” the black via a Luma Keyer, and cut the black out. It was an imperfect system, which only allowed hard edges, but it worked if you had a director who knew their keyer. You, luckily, won’t have to deal with this, but here’s a good treatise from a guy who knows his Superblack:

    https://forums.creativecow.net/thread/202/878966

    Joe Bourke
    Owner/Creative Director
    Bourke Media
    http://www.bourkemedia.com

  • Ron Moore

    March 21, 2013 at 2:10 pm

    I rendered out a TIFF sequence from C4D to After Effects so I do have transparency in AE but when I rendered out the 25sec animation with the Animation codec to preserve the alpha to go into Premiere it was over 7GB! Can’t I just save as a Premiere Pro project file and skip the AE rendering and assemble the rest of the project over in Premiere?

  • John Cuevas

    March 21, 2013 at 2:27 pm

    You should be able to do what you want. I dont’ dynamically link much(use an Avid), but if I remember correctly, you need to save your AE project, open premiere, then open the AE Project/Comp using Bridge.

    Johnny Cuevas, Editor
    Thinkck.com

    “I have not failed 700 times. I have succeeded in proving that those 700 ways will not work. When I have eliminated the ways that will not work, I will find the way that will work.”
    —THOMAS EDISON on inventing the light bulb.

  • Ron Moore

    March 21, 2013 at 3:08 pm

    Thanks, I’ll give it a try over in Premiere. The destination is a .wmv so I just need that alpha to composite a background and save it as a sequence, so that will probably work.

  • Joseph W. bourke

    March 21, 2013 at 5:43 pm

    …and I always thought Superblack was a Seventies movie starring Ron O’Neal…

    Joe Bourke
    Owner/Creative Director
    Bourke Media
    http://www.bourkemedia.com

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