• Adobe After Effects

  Troubles with Alpha

  Posted by Bob Cole on October 23, 2006 at 12:50 am

  I’m hitting the same invisible wall over and over here, so I thought I’d ask you-all.

  I have a graphic with multiple windows in it, each of which I’d like to fill with different moving video. Sometimes I’d like the same piece of moving video to appear in neighboring windows.

  My first plan was:

  1 – In Photoshop, I created different versions of the graphic with a separate alpha channel for each different “window.”
  2 – In AE, I created separate comps for each window, then
  3 – combined them into one comp so that the various windows’ video would add up to one wonderful dazzling whole. The graphic itself would be Layer 1 in that final comp.

  For whatever reason I can’t seem to get any of my alpha channels to work in AE. I’ve tried reinterpreting, and re-importing.

  How would you approach this? Should I be using black and then keying it out?? Or multiple masks, which I find tough to manage?

  Thanks for any insights. Sorry if this is a dumb question.

  — Bob C

  Mark replied 19 years, 10 months ago 3 Members · 2 Replies
• 2 Replies

• 

  Mike Clasby

  October 23, 2006 at 2:51 am

  If you had transparency in PhotoShop and exported your PhotoShop File as a psd, you should be fine, and when you import it you can import as a composition if that makes it easier, use the top dropdown in the Impost window, Import Kind>Composition.
• 

  Mark

  October 23, 2006 at 11:16 am

  I think that I would have created a still for each window. Not an alpha, but rather a matte (black and white image). In your seperate comps, you can then select to use the luma levels of the stills as track mattes for your fills.

  Mark

Reply to this Discussion! Login or Sign Up