Polarizing filters questions

[P3D Dr. George A. Themelis <fj834@xxxxxxxxxxxxxxxxxxxxx>]

I see Edmund Sci. lists two kinds of polarizing filters for sale:

1. Commercial grade w/25% transmission and
2. Tech Spec w/38% transmission.

The Tech Spec material is a little bit more expensive but not all that
much.  Does any one know what kind is Reel 3-D using?  I went ahead and
ordered both and plan to experiment.

It's been said that one of the weak links in projection is the glasses that
the audience wears.  Is the material in these glasses about the same
quality as the filters in the projector?

Finally, does it make any difference if the filters are placed before or
after the slide?  If it does not make any difference in terms of light
extinction then they might as well be placed before the slide to reduce the
energy hitting the slide.

To optimize projection condition one has to take into account all the steps
involved:  Light bulbs, condenser system, polarizing filters, lenses,
screen, polarizing glasses.  It makes no sense to optimize one and ignore
the rest.

George Themelis


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