Blue or green background color?

I have several questions concerning blue or green background colors used for
separating the foreground from the background:

1. Why blue or green?
2. Does it matter which color?
3. Does the shade of either color matter?
4. Whichever color, it usually spills over or reflects in the highlights of
hair. What is the best way to get rid of this?
5. Have I forgotten anything regarding the background color of what to
do/use to get rid of the spill over in hair?

Thanks.........

 

No. as long as your device or software can 'tune' to that color.

Absolutely even lighting on the screen!
A bit more physical separation helps too, but that means a bigger
set/screen.

 

I think I mis-stated my issue: I have read many times that, if you know
ahead of a shoot, you should use either a blue or green background (like the
pros do in movies). This makes it much easier to separate the foreground
from the background using software.

 

It's not that simple. Read more on what it is here:
http://www.seanet.com/Users/bradford/bluscrn.html

 

.... to which I answered your query from BOTH a TV and Photog point.

 

What is the best software to separate the foreground from the background?
Or, what are the alternative softwares out there? Thanks......