Re: Polarization of IR

[David Dockstader <DRDOCK00@UKCC.UKY.EDU>]

On Wed, 03 Jun 1998 12:07:04 -0500 Gary Karshner said:
> Ken,
>        Your correct Polaroid film does not work well in the IR. You might
> try it with the green or blue filter from their set. Watch out for these as
> well, red and yellow filters usually pass the near IR as well as violet and
> some blue filters.
>        I learned about Polaroid film from warnings about using it during
> solar eclipses. Crossed it block the visible light so your eye dilates but
> lets through the IR that can burn your retina!

I never really thought much about this before, but I suppose the same problem
exists with UV, so polarizing sunglasses are probably a bad thing unless they
incorporate UV and IR absorbing material along with the polarizing material.