P3D Re: 3D Stewart Film Screens

["Greg Wageman" <gjw@xxxxxxxxxx>]

From: Charles Pflanze <cwpf@xxxxxxxxxxxxxxxxxxx>


>Is there anything special or high-tech about these silver projection
>screens?  I've two in my collection, a 40" and a 50" - they seem to
>covered with very thin, hardly noticeable vertical lines extending from
>the top to the bottom of the screen.  What's the purpose of the lines.

They're called "lenticular screens", and the "lines" are lenticules.  A
silver screen is a specular reflector, like a mirror (angle of incidence
equals angle reflection).  Since the projector is typically centered on
(normal to) the screen, that means the image brightness of a flat silver
screen will fall off rapidly as you move off-axis.  The lenticules are
there to provide a surface to reflect some image off to the sides, to
help boost off-axis brightness.


>Is it possible to create an 8' x 10' silver screen by merely painting a
>smooth wall of a large room with silver or aluminum paint? (do this
only
>at home, of course!)

Apparently so, this has been discussed here.  Some brands of paint are
apparently better suited than others for this purpose.

     -Greg W. (gjw@xxxxxxxxxx)