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keying and alpha channels,

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jack entonces
keying and alpha channels,
on Jan 27, 2007 at 2:27:31 pm

I am having the hardest time understanding how to keys and alpha channels work, much less how to incorporate them into graphics on my video.
Can someone recommend a book, tutorial, or webpage that explains
the concept and technique of working with keys and alpha channels?
Thank you.

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Re: keying and alpha channels,
on Jan 27, 2007 at 3:42:30 pm

Hi Jack,

Basically, keying is separating an element out of a picture or scene. If you make a selection, you can save that selection as a "mask". The pixel information of this "key" or "mask" is stored in an Alpha channel, so you can reselect and make changes to it it at any time.
You can either manually build your mask ( key), or use "plug-ins" to make the process of selecting easier.

If you save a picture or video with alpha channels ( choose a format that supports Alpha channels like Photoshop "psd' or AE "Quicktimes Millions colors +" format ) you can import the files into other applications and do whatever you need to, to either to the Alpha and/or the "masked out' elements.

But this is really only a very very basic explanation. Search the Cow, you'll find tons of info on keying.
Or check out this link, which contains great info as well:

That'll get you started ;)
Take care.

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Richard Harrington
Re: keying and alpha channels,
on Feb 4, 2007 at 7:31:42 pm

There is a bok called Photshop for Nonlinear editors and its companion website Photoshop for Video that go into nauseating detail on tiopic

Richard M. Harrington, PMP

Author: Photoshop CS for Nonlinear Editors, Understanding Adobe Photoshop, and ATS:iWork

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