Does a Dark Desktop Image Help Save Battery Life?

Question

I know this is a weird question.
But think about it: if you use a very bright desktop image, say something like this: http://img64.imageshack.us/img64/4540/deserttoyota24wf.jpg
and if, in the second case, you use a quite dark one, with a lot of "black" pixels that actually does give a lot less light (the one here is my desktop picture, a map with a light-rendering effect):
http://img64.imageshack.us/img64/8049/europewidefx7wq.jpg
1. does the darker desktop screen consume less battery power for the smaller amount of "glowing" pixels?
and, as I am asking stuipid questions,
2. does the darker screen help in prolonging your Powerbook screen's lifespan?
I have been asking myself these questions ever since I got my brandnew PB 17" HD (October 2005), and although they seam strange I am serious about it.
Thanks!
PowerBook G4 17" 1.67 HD + G4 QS 867   Mac OS X (10.4.5)  

Answer 1

Your backligth seems to be white is'nt it ?
So to known how much you use electric power to switch a pixel from white to black, the best way is:
1) to turn off all your ligths in your house
2) to remember your electricity company counter index
3) mesure the time the powerbook is on
4) put your screen with a white background
5) change the background to black
6) run to the electricity company counter and write down the index
7) substract the start index from the end index
8) substract powerbook electric comsuption
9) divide this result by the number of pixel your LCD have it will give you the electric comsuption for one pixel.
Hope this help
:-))