• Adobe After Effects

  Render black as alpha

  Posted by Stig Olsen on April 28, 2014 at 9:37 am

  Hi,

  I just got an animation without an alpha channel. The area that is supposed to hold the alpha is black. Can I render this black as an alpha channel?
  I know I can screen the footage onto the background but I need to make this clip with an alpha channel.

  Stig

  Stig Olsen replied 12 years ago 2 Members · 4 Replies
• 4 Replies

• 

  Walter Soyka

  April 28, 2014 at 2:12 pm

  https://www.redgiant.com/products/all/knoll-unmult-free/

  Walter Soyka
  Principal & Designer at Keen Live
  Motion Graphics, Widescreen Events, Presentation Design, and Consulting
  RenderBreak Blog – What I’m thinking when my workstation’s thinking
  Creative Cow Forum Host: Live & Stage Events
• 

  Stig Olsen

  April 28, 2014 at 3:12 pm

  Hi,

  Umult makes the rest of the graphic about 5-10% transparent.

  Stig
• 

  Walter Soyka

  April 28, 2014 at 3:33 pm

  You can use the Levels effect after Unmult to tweak the alpha levels. You may need to combine this with some color correction if it pushes your colors too far out.

  Alternately, you can use Extract to pull a luma matte, but you may need to work on the edges a bit.

  Walter Soyka
  Principal & Designer at Keen Live
  Motion Graphics, Widescreen Events, Presentation Design, and Consulting
  RenderBreak Blog – What I’m thinking when my workstation’s thinking
  Creative Cow Forum Host: Live & Stage Events
• 

  Stig Olsen

  April 29, 2014 at 8:06 am

  Thank you!!

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