Creating a mask using channels in CS3?

[V8burble]

I'm sure I saw a U-tube tutorial on how to create a mask of a lady with a difficult background... I'm sure it used channels and saturation/levels etc to obtain black/white edges to the complex shapes to create an accurate mask? But I can't find it now. Has anyone got any idea what I'm on about LOL?

Thanks

 

[Tyke Tiler]

Wasn't this was it?

http://www.youtube.com/watch?v=83FHUzQ8s5E&feature=related

I got a lot of results when searching for 'layer masks using channels'

 

[V8burble]

Thank you Thomas, similar but the one I found before was of a lady outside in front of some bushes, it took a fair amount of fiddling to achieve a mask, but it was very clever... I'll have another search. Thanks for trying