filmscanners: This Gamma Thing...?

[Tom Christiansen <tomchr@softhome.net>]

Hi,

I've learned a new word today: Gamma.

It's something with the way monitors show images, but what exactly is it?? 
I notice that my scanner software has a gamma adjustment and playing with 
it I noticed that it changes the way the image appear on the screen.

But what exactly is this mysterious gamma thing?

My scanner software defaults to gamma=1.4. It this an optimal value? If 
not, what is a better value?


I'd appreciate some scientific facts about this gamma.


Thanks,

        Tom