If found near the Akku a screw, here you can adjust the contrast!
I rais up at my Prs600 at 100%, The Pictures in the (Ebooks) are not so bretty but the Letterīs are realy cool and better to read!
Sorry SONY but the PRS 600 was and is a mistake from you!
If you adjust the screw you must go to the next site (ebook) to see result!
You need a very small screwdriver!
All of this TIPS without waranty!!! THIS TIPS ALL OF YOUR OWN RISK!!!