one-colour effect

Hey,

How can you create (e.g. in After Effects) the effect where everything is in black&white except on coulor or coulor range?
For example, when you shot some people wearing yellow T-shirst on a grass field, with the effect applied and set on yellow, everything is B&W exept for the shirts.

Thanks in advance, WVD

I don't know of any color range selection in AE or any programs.
Most people would put a mask around the shirts and rotoscope the position. Ten you could duplicate the video layer and take out the color. The effect is that anything within the mast will be B&W and anything within the mast will be the original color.

There was a car commercial a while back that had a red car driving down a road and the car was the only color in the video. I asked my teacher at the college how they did that one and he said they masked it out.
So yea, same effect, different situation.

Found it! This effect is known as the Sin city-look.

Example from what I made: http://gottalaunch.com/pictures/_img/thebigtest_boyan.jpg