Easy test to see of windshield is killing detection range

[TheTexan]

Just noticed this today when I was driving around town. If you are wearing polarized sunglasses and look at a car windshield which has the metalic film between the layers that many people have said kills detection range, it apears very bright orangish color almost like well coated optics on rifle scopes or rangefinders would look, but even more so (so much to where I could barely even see through the glass mith my specs. on). I pulled my glasses off to see if it was apparent without them and the glass looked like normal old glass. The types of cars I noticed this on were a lot of GM cars like high end buicks. If I remember right Mike V mentions many of these cars have unnacceptable windsheilds.
That being said, if you have been getting real bad range, buy or borrow a pair of polarized specs and take a look in sunlight at the glass, you might be suprised at what you find. I also noticed the glasses had the same effect on metallic versus just plain tinted windows. Im pretty sure it is because polarization of the lenses takes the glare off of the surface of the glass (reason they are popular with trout fiisherman, makes the water more transparent) thus allowing you to see direct sunlight reflected off the metallic layer, just a thought though.

[Sparkknocker]

Very good information. Thanks for the post

[bauzer71487]

No kidding, great find!!! :P

[Switchback]

I think what you are seeing is a polarizing filter within the glass. (I have worn nothing but polarized specs for 20 years).

If you tilt your head or glasses to the side at exactly 90 degrees any other polarized material will become an opaque black! What is happening is the polarization filter is doing excatly that. it is polarizing, neaning it is blocking all or most of the vertical rays of light. because the lines in the filter are horizontal. so when you turn the glasses 90 degress one filter is blocking vertical light, and the other is blocking horizontal light, making it black (no light allowed through)

Yes most high-end GM vehicles doe have a metallic substance in the windshileds similiar to coating used in hihg-end optical equipment.
But, did you know most headlights are polarized? this is to not blind other drivers. Henry ford tried to get a law passed that all windshield glass must be polarized for this very reason. ( way way back when)

I believe a more exact way to tell if you have a metallic layer in your windshiled is to research the manufacturers website. And metal layers within glass will almost always have a blue metallic hue or an orange/red hue when observed with the naked eye.

But good observation Texan!

And it is more than trout fisherman that wear polarized, it is all of us tournament contenders or any other fisherman that is worth a darn.

Also, for your own protection, get polarized glasses!!! you only get one set of eyes, and if you feel your eyes are only worth $5.00, then only get $5.00 glasses. Like RD's, get the best protection you can afford. retinal burns happen over time in any light condition, and real fast out on the water (frozen or soft) or on the roadways.

[TheTexan]

switchback, the window wasnt black it looked like it was covered in a film of polished copper it even had defined edges that did not cover the enitre widshield(it almost looked like it had holes in it where many temp and other sensors are on the windshield) and was only apparent when I was looking straight ahead and when I removed the glasses the glass just looked like glass. When you are wearing your glasses next time look at the windshield of a buick Ranier, I have seen a lot of those with this effect.
I know what you were talking about with going dark effect, my computer screen is polarized and will go black if I turn my head like you said.