rodrad

MP4.2+6.0

Are your windows--including rear--aftermarket tinted? An educated guess...

rodrad

MP4.2+6.0

Look at the edges of the window and rear glass where they transition from transparent to black/opaque on the inside of the glass near the frames, roof and C pillars. At the transition point are some little black dots on the inside of the glass--how they help fade that hard black visual line. If you see what seem tiny air bubbles right around some of those dots, there is window tint. Tint can be as light as 90% (10% darkening), which in ceramic still blocks a bunch of heat. Bigger picture, I have avoided tint on the back glass because of these kinds of visibility issues at night with the defroster and antenna wire lines. Sort of aggravating when you look in back window with traffic behind you and you see those lines diffracting glare. Having seen the effect on my D3, I consciously had only side windows (and sunroof panel) tinted on mine. And thus, I don't have any obvious rear glare diffracting around those factory defroster and antenna lines with my D4 S8.

rodrad

MP4.2+6.0

I know from my D3 where I had it tinted and then first saw the lines. Similar result on a Mini S and then our Q5 with rear tint, though on both of those since glass is less angled than a D4 or D3 you don't notice it as much. I used the same tint shop and same tint brands and types on them. Why as a conscious choice I avoided the rear glass on the more recent D4 S8 when I had it done, and instead tinted the sunroof glass to approximate the same heat load reduction.

Another board member commented similarly BTW when I mentioned this issue in recent years. Maybe Derf?

You have to be careful removing rear tint because of you break those lines (like w/ a razor blade) it destroys the antenna or defroster functions. Best to have a pro do the rear glass with the steam type equipment.

rodrad

MP4.2+6.0

Not in the way you are thinking. Audi glass is tinted by 30% from the factory IIRC--the max allowed by regulation--but that is a permanent coating or other process done during glass manufacturing, not a tint film. If you see the little air bubbles or look around those face dots I mentioned, that pretty much says there is an aftermarket tint on that piece of glass. A tint shop of course can look at it and confirm.

rodrad

TheoRR

I have a very light tint applied to the rear window. As a results, the rear window does creates a vertical glare just as described by the OP.

Easy way to visually check if there is a tint applied is to look around the third brake light. The cut out for the brake light tends to be manually done, so you should be able to see some rough edges to the tint material, if there is one applied.