Originally Posted by kacir
I am not sure if you save your battery if you switch off the inversion.
There are two kinds of screen update. A local update that is used by default by all manufacturers in menu and whole screen update that is used by all manufacturers when turning page.
Local update is quicker, but it doesn't clean up the previous image completely. So you see "ghosting".
Most people stop noticing the inversion after relatively short use and I guess that manufacturers didn't want to risk people complaining that there is residue from previous image / page when they turn the page.
Thanks for the reply. Really helpful.