On Mon, 15 Feb 2010 19:04:51 -0800 (PST), JIMMIE
wrote:

A different perspective on polarization loss?

Different? How? All pretty standard stuff.

As for different literal perspectives of polarization, I am sitting
here with two sets of 3D glasses for "Avatar" (just got back from the
IMAX version) and these two pair of glasses are very different from my
experience with Polaroid lenses of days gone by. And they are very
different from each other for the same movie.

The Real3D glasses at IMAX didn't work as normally worn, I still saw a
double image; but viewing the movie through the lenses backwards (ear
pieces going forward) rendered the IMAX 3D as 2D.

Now, when I sit here at the console and view the display (flat screen)
through the IMAX lenses, I can dim the display by rotating the pair.
One eye piece goes black at 45 degrees rotation, and the other eye
piece goes black at -45 degrees rotation. Flip them to look through
them backwards, and the same effect is observed.

When I take the Real3D pair and rotate them, only a slight shift in
hue: yellow tint in both lenses at 45 degrees rotation, and a blue
tint at -45 degrees rotation. When I flip them to look through them
backwards, I encounter a slight brightening for both lenses at 45
degrees rotation and a complete blocking for both lenses at -45
degrees.

I am familiar with display technology employing LCDs with double
polarization to increase contrast, and I could easily expect this from
the lenses of these two pairs of 3D glasses. Without having gone
further into researching it, I have a hunch that I am encountering
circular polarization here.

A little digging will tell.

73's
Richard Clark, KB7QHC