Check out new commentary for the TMP Director's edition....
http://www.startrek.com/startrek/view/features/bst/article/2301143.html
They also explain the deflector dish changing colors. It is gold/brown when it is in a low power state because the engines are powered down, and turns blue when the engines are online.
http://www.startrek.com/startrek/view/features/bst/article/2301143.html
They also explain the deflector dish changing colors. It is gold/brown when it is in a low power state because the engines are powered down, and turns blue when the engines are online.