horn13 said:
If you take two identical pairs of polarized sunglasses and hold them up together so that you can see through both lenses, if you rotate one set of the lenses 90 degrees the lenses won't permit light to pass through. They go black.
Just a quick way to test the validity of having polarized glass.
Thats right, best way to determine 100% polarized is rotate 90 degrees.
The polarization is basically bars like a window shade.
Crossing the polars "should" eliminate the light.
Some might let light through that means the polarization is not complete.
I've tried some that only dim the light but say they are polarized.
Manufacturers despise educated shoppers.
Its buyer beware.