hello everyone.. thanks for reading my post. I recently noticed that sometimes when backing up a DVD, the DVD will sometimes have dark discolorations on the bottom. I played one movie I burned that has these discolorations, and it played fine. But the discoloration bothers me. Usually it's just a dark spot or 2 on the bottom of the DVD but sometimes it's a streak. I have noticed this when I burn at 4X. When I burn at 2X I don't notice the problem. I will start burning at only 2X.. but does anybody have any idea why this is happening? I have a SONY DRU510A 4X DVD Burner. Thanks. EDIT: I have noticed the problem on 4X Samsung media and Ritek GO4 4X DVD-R.