Newbie: Retain transparency (alpha channel) in AE for cloud.mov assets

ActionVFX
1

So in After Effects, when I import storm clouds as .mov files, the background is black (no transparency and the background is block). I can’t key on the color black as the storm clouds are very dark. I’m guessing that somehow during the import AE isn’t recognizing the alpha channel?

-Jeff

2

For assets that consist solely of luma (brightness) information (and no color) you can simply substitute the alpha by the luma, if they are shot on black BG.

  • Load the clip into an AE layer
  • Add a “Set Channels” effect
  • Set the “Set Alpha To Source 4’s” to “Luminance”

You can then leave the RGB as is or (most of the time better) add a “Fill” effect and fill the RGB with the color/gray of you choice.

You can then also adjust the Alpha with a Curves effect to make it more opaque/transparent (make sure to only effect the Alpha in the Curves effect for that).

J.

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