P3D 3D Stewart Film Screens

[Charles Pflanze <cwpf@xxxxxxxxxxxxxxxxxxx>]

In a previous post, Michael Kaplan <view@xxxxxxxx> wrote:
 
>I was using a Stewart 11' x 14' silver screen at the University of          
>Tennessee,
 
Well, shucks, if that's the Knoxville campus, I live only 3 miles
away, I may have missed something . . . 
 
>and it's a beautiful product - complete with demountable         
>aluminum frame. I've always thought NSA should invest in one of these.      
>There's a big difference in seeing a Realist-format slide 11' x 11'         
>instead of 7' x 7' as on the NSA screen.
 
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.
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!)
 
Charles