whoa.. this is interesting. So much of physics and optics here!
can you please explain how can you control the region of yellow, blue, violet, green etc?? Can you actually know which color cast a particular area will be and to what extent?

Ashwin, while this takes the colors to extremes I think there may be some good possibilities to use this technique to create some interesting B&W images.

Sandeep, by rotating the polariser you can control the region of colors in the frame. Through the view finder you can only see a hint of yellow and green. Rest come only after exposing the frame. But after taking some shots you ca easily guess what would come where!

Ganesh, that a nice idea! I would try that...