[simpits-tech] Rear projection material+mylar mirrors+projector ratios

[Alan D. Mazurka]

Brian,

good to hear from you.

mine mixed with yours:

At 03:47 PM 1/22/2008, you wrote:
>Three quick questions:
>
>First, I vaguely remember someone posting a bit back
>about rear projection materials. Someone mentioned
>something that worked really well, but was on the
>pricey side - could whoever it was fill me in on the
>details?

someone will give you better guidance here. the backside of most 
rear-projection screens has a printed fresnel pattern to break up the 
"hot spot" you'll otherwise see from the projector.

>Secondly, I was wondering if anyone here had played
>around with making a lightweight mirror out of mylar
>before. I was poking around for some info yesterday
>and I found a pretty neat system for pulling all of
>the corners tight, seeming to me to make a pretty
>distortion-free reflection. Just wondering if anyone
>here had played with it before.

precision is the only thing that's going to keep enough quality when 
you bounce an image. i have bad feelings about the mylar trick, since 
you won't be able to get it flat enough. those front-bounce mirrors 
are figured to a very high degree of flatness.

there must be lots of optical-quality mirrors piling up as those 
dinosaur-sized 3-gun rear-projection TVs find they way to the 
landfills. sometimes i see them in those salvaged electronics 
catalogs, usually pulled from copiers.

>And finally, I was wondering if anyone had any good
>info on the ratio of projector distance vs. image
>size. I'd imagine it probably varies somewhat with
>projector model, but a good ballpark figure would be
>nice.

try the "projector calculator"

http://www.projectorcentral.com/projection-calculator.cfm

if you just toss some projector models at it and notice the lens 
specs, you'll get a good ballpark guess.

>Brian
>
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all the best,

  - adm -



----------

Alan D. 
Mazurka 
adm.design at verizon.net
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