Please help me out. Usually when you burn a CD or DVD, the color of the data film will changed. For my DVD-R, it changed from Dark to Lighter. When I try to burn my DVD-R as DATA, I notice that there's a Dark Ring located in the middle of the data area (the middle from the Center to the edge of the disc)

It's similar to when I tried to burned a 2 session Audio CD; Whereas on the CD, the first session is playable while the 2nd session only works on comp. That Ring on my ALL DVD data discs look just like the space between the session on that type of Audio CD.

Can anyone tell me what might be the cause?

My DVD-R/-RW burner is Pioneer DVR-105

The media I used is unknow, I bought them on Ebay, please don't laugh, and it's 4x DVD-R. They works good 95% of all the time. It has GOLD top and Purple bottom just like the good old Verbatim CDRs