• Adobe Photoshop

  Pre-multiplied,Matted Alpha Channel

  Posted by Andrei Firtich on February 16, 2006 at 8:06 pm

  Hi, I am an After Effects user, when you render a file in after effects you get an option to pre-multiply or not your alpha channel. Photoshop does not give you this option, Here is a visual example of what I’m talking about, Here is Photoshop version
  Here is the pre-multiplied After Effect Version
  My question is how do you premultiply or matte the alpha channel in Photoshop
  Thanks in advance

  Richard Harrington replied 20 years, 3 months ago 2 Members · 3 Replies
• 3 Replies

• 

  Richard Harrington

  February 17, 2006 at 12:19 am

  Can’t do it automatically

  Two real options

  If Photo.. create tranparenct with layer mask…. then disable layer mask and let alpha channel cut hole

  if graphic… fill color of glow or shadow in as a solid background layer after creating the channel

  Richard M. Harrington, PMP

  Author: Photoshop CS for Nonlinear Editors
  Co-Author Final Cut Pro on the Spot, After Effects on the Spot, Broadcast Graphics on the Spot, and After Effects @ Work
  Check out the new DVD: Photoshop CS: Essentials for Digital Video from http://www.photoshopforvideo.com

  edit – produce – direct –
• 

  Andrei Firtich

  February 17, 2006 at 12:40 am

  Works like Charm
  Thanks
• 

  Richard Harrington

  February 17, 2006 at 2:44 am

  Good….

  Check out PS NLE book or photoshopforvideo.com for videos on this and more

  Richard M. Harrington, PMP

  Author: Photoshop CS for Nonlinear Editors
  Co-Author Final Cut Pro on the Spot, After Effects on the Spot, Broadcast Graphics on the Spot, and After Effects @ Work
  Check out the new DVD: Photoshop CS: Essentials for Digital Video from http://www.photoshopforvideo.com

  edit – produce – direct –

Reply to this Discussion! Login or Sign Up