Black and White Alpha Masks

An example of what I'm talking about would be this one: http://www.pond5.com/stock-footage/122857/playing-cards-3d-animation-ntsc.html

How do I make use of it?
Programs I could do it with would be appreciated.

You can change the green background to anything you like. You can use the Adobe AfterEffects to make the background transparent.
Zygis

I just facepalmed.

*sigh*

If you look a little further, you'll see a Black and White version, with White apparently being what's preserved, and Black being what's not.

Is that what you're talking about?...

Correct. It's called a "luma matte". Think of the white as a "light"... you see where the light shines and you don't see where the dark is.

"Think of the white as a "light"... you see where the light shines and you don't see where the dark is." That is right for Premiere and for the vast majority of the NL editors. But, if you are on an Avid machine, for "historical reasons", the things are reversed.

God bless us all!
Christian

Green Ghost,

Try this http://en.wikipedia.org/wiki/Alpha_compositing and simply google http://www.google.co.il/search?hl=en&rlz=1C1CHMB_iwIL346IL346&num=100&newwindow=1&q=alpha+matte&btnG=Search&meta=&aq=f&oq=

You obviously have to split the clip in two halves first though. The colour part is used as any clip would, the black and white is used to "mask" the colour part, i.e. to define what's visible and what isn't.

Of course depending on what software you use, you could just tell the software to bring in the clip as matted or pre-matted and then you really don't need the "2nd half" provided the clip is already keyed and has an alpha channel.