• Adobe After Effects

  alpha channel probelms with tgas

  Posted by Ian_mac on March 28, 2006 at 1:21 pm

  Please help me!!!
  Every time i render a targa sequence with a straight built in alpha (with a black backgnd in the composition), the rendered targa stills have a dfferent coloured alpha backgnd.

  Why is this happening?
  Is it a bug?
  Can i resolve it?

  Help!!!!!!
  Thanks
  ian

  Christopher R. green replied 20 years, 1 month ago 3 Members · 4 Replies
• 4 Replies

• 

  Steve Roberts

  March 28, 2006 at 2:16 pm

  If you have rendered with “straight alpha” to a format that supports millions+ colours, then your backgrounds should be transparent.

  In which application do you see these different coloured backgrounds in the imported rendered TGAs?
• 

  Ian_mac

  March 28, 2006 at 2:36 pm

  only when i open them in the preview application.
  They are fine in photoshop.
  I’m just concerned because i then have to import it into Clarity to go to transmission and was told i had to render with a black backgnd.

  I too thought i would not matter if it was a straight alpha.
• 

  Steve Roberts

  March 28, 2006 at 3:30 pm

  I’d guess that the Preview app doesn’t know what to do with alpha channels.

  Have you sent a test to the Clarity? If I were unsure, that’s what I’d do.
• 

  Christopher R. green

  March 29, 2006 at 2:50 am

  Make sure you have 32bit selected in the targa options dialog when you render in ae.

  … maybe this is the issue ?

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