It is very expensive print the real book with white letters on a black background, but with ebook readers it could easily be possible.
So i wrote an email to the Kindle feedback service:
i’m an italian user of kindle 3.
Is it possible to read on kindle in a negative mode, with white letters and black background?
If not, could it be possible in the future?
and they replied me:
Hello, I’m sorry, currently its not possible to view books in negative mode on Kindle device. We’re regularly working on improvements to your Kindle experience. I’ve let the Kindle team know you’re interested in this feature. etc etc
Ok i’m awaiting this useful feature.