FX Shot with DVX

[CaptainWhacky]

I'm about to help a friend of mine shoot a short with my dvx and there's an fx shot that she wannts that I can't figure out how to do. So I was wondering if anyone here could help me figure something out. She wants to have it where there is an imaginary person that the main character sees that is from 1930's movies. She wants that imaginary person in B&W like a 30's film while everything and everyone else will be in color. Any idea how we can pull this off without using green screen. I have access to After Effects and Motion. Any help is appreciated.
__________________

 

[Greggl]

Rotoscope and desaturate.

 

[Andrew Brinkhaus]

That pretty much nails it. LOTS of time rotoscoping and i'm sure you'll get what your looking for.

 

[CaptainWhacky]

I knew the desaturate part, which program would be better for rotoscoping, AE or Motion. Please note that I have never done any rotoscoping. If anyone can thing oa an easier or faster way than rotoscoping please also let me know.