What is Alpha channel and matte ? at DVinfo.net

Arthur Abramov · June 10th, 2009, 10:25 AM

these terms - alpha channel and matte?

can anybody explain how are they work in photoshop or after effects. i'm learning after effects now and i'm having a difficulty with understanding these terms..

i'm sure this question is silly for the pros but what can you do :)

Thanks,

Cole McDonald · June 10th, 2009, 11:36 AM

The alpha channel is a black and white channel of an image (the "A" in RGBA) that says how transparent each pixel is. White is Opaque, Black is transparent. In between is in between.

A matte is that which defines the alpha channel (kinda abstract). Often, this is simply a chunk of the image that is masked off by the editor/ compositor.

Ray Bell · June 15th, 2009, 04:45 AM

a good example would be if you wanted to put on a title and have the video play behind
the letters in the title.. the title would be Alpha matted, sos the title would have zero
opacity and the matte would define the letters in the title.

June 10th, 2009, 10:25 AM	#1
Arthur Abramov Regular Crew Join Date: Dec 2008 Location: new york, Israel Posts: 136	What is Alpha channel and matte ? these terms - alpha channel and matte? can anybody explain how are they work in photoshop or after effects. i'm learning after effects now and i'm having a difficulty with understanding these terms.. i'm sure this question is silly for the pros but what can you do :) Thanks,

June 10th, 2009, 11:36 AM	#2
Cole McDonald Trustee Join Date: Nov 2005 Location: Sauk Rapids, MN, USA Posts: 1,675	The alpha channel is a black and white channel of an image (the "A" in RGBA) that says how transparent each pixel is. White is Opaque, Black is transparent. In between is in between. A matte is that which defines the alpha channel (kinda abstract). Often, this is simply a chunk of the image that is masked off by the editor/ compositor. __________________ Web Youtube Facebook

June 15th, 2009, 04:45 AM	#3
Ray Bell Regular Crew Join Date: Nov 2004 Posts: 1,414	a good example would be if you wanted to put on a title and have the video play behind the letters in the title.. the title would be Alpha matted, sos the title would have zero opacity and the matte would define the letters in the title.