I was playing around with two polarized filters the other day. I was actually on the highway at the time. Something that I noticed when I had them aligned to block out all light, the only light that seemd to make it through was red. It was pretty cool looking to look at all the oncoming car's headlights (which we should know are white) and only seeing little red dots. I would imagine this is a result of where red stands on the spectrum. This was actually surprising to me, because I was unaware that the frequancy of light had any impact on polarized filters. Plus even if it does, I would have thought the higher frequencies would be the ones able to penetrate. So anyway, question is why red?