Geometry Problems on Portable Screen with Short-Throw Projector - AVS Forum | Home Theater Discussions And Reviews
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post #1 of 9 Old 02-25-2018, 03:37 PM - Thread Starter
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Question Geometry Problems on Portable Screen with Short-Throw Projector

I've got an Epson PowerLite 450W ("ultra") Short-Throw projector, which is missing its wall mount, so I currently have it sitting on the floor. Unfortunately, even though it has very good geometry on its own, the minor folds in the Da-Lite Insta-Theater projector screen (100" 4:3) lead to some rather unfortunate geometrical distortions on the left and right edges, but mainly all across the top of the image, especially toward the upper-left and upper-right corners.

I've tested it with an old not-so-short-throw projector and found that the issues don't really manifest with that, so I don't think that there's anything too terribly out of whack with the screen, it's just not flat enough to work really well with the short-throw machine. My question is if there is anything I can do to help the screen material return to a neutral shape so that this issue can be reduced or eliminated.
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post #2 of 9 Old 02-25-2018, 04:16 PM
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That’s a tough one. With the short throw every imperfection will be magnified as you are seeing. I don’t know of any method of eliminating the normal imperfections of the screen.

Maybe try over scanning the screen and let the masking straighten out the edge.

You could ask Da-lite if they have suggestions.

Maybe someone will be along with more help.

Bud
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post #3 of 9 Old 02-25-2018, 05:23 PM
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the Insta-theater came with a gain screen (2.2 gain if I remember) which will not look good with a short throw projector
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post #4 of 9 Old 02-26-2018, 05:03 PM
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Quote:
Originally Posted by Ellebob View Post
the Insta-theater came with a gain screen (2.2 gain if I remember) which will not look good with a short throw projector
While some Insta-Theater screens came with 1.0 gain matte white screen material the 100" version did only come with the 2.2 gain Wide Power (not to be confused with High Power) acetate screen material. You're right that this would be a poor choice for a UST projector with its acute angle throw. It's highly recommended to only use fixed screens with either matte surfaces or an ALR material specifically designed for UST use. UST projectors will accentuate every irregularity in a screen that isn't absolutely flat, and fixed screens are the flattest available.
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post #5 of 9 Old 02-27-2018, 03:15 PM - Thread Starter
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Post I was afraid of that... time to move on from short-throw perhaps

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Originally Posted by bud16415 View Post
That’s a tough one. With the short throw every imperfection will be magnified as you are seeing. I don’t know of any method of eliminating the normal imperfections of the screen.

Maybe try over scanning the screen and let the masking straighten out the edge.

You could ask Da-lite if they have suggestions.

Maybe someone will be along with more help.
Thanks for the suggestion. I got in contact with the Da-Lite support center, but they also advised me that this screen is not optimal for short-throw projectors.

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the Insta-theater came with a gain screen (2.2 gain if I remember) which will not look good with a short throw projector
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Originally Posted by Dave in Green View Post
While some Insta-Theater screens came with 1.0 gain matte white screen material the 100" version did only come with the 2.2 gain Wide Power (not to be confused with High Power) acetate screen material. You're right that this would be a poor choice for a UST projector with its acute angle throw. It's highly recommended to only use fixed screens with either matte surfaces or an ALR material specifically designed for UST use. UST projectors will accentuate every irregularity in a screen that isn't absolutely flat, and fixed screens are the flattest available.
Gotcha. That makes sense, especially given how much light seems to get reflected onto the ceiling. Normally, this would be somewhat concerning, but the PowerLite is so surprisingly bright that there was still plenty of light to work with. Sounds like I'd be better off trading this in for a "normal" throw projector though in order to combat both issues.
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post #6 of 9 Old 02-28-2018, 05:47 PM
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@Browningate , yes, either trade in the projector for a standard throw model to use with that screen or get a new screen that works better with UST projectors. Wide Power is a unique material for front projection that has been variously described as acetate, mylar or acrylic. I believe it was only offered by Da-Lite and there is very little user information available about how it actually performs in home theater use.
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post #7 of 9 Old 06-07-2018, 04:12 PM - Thread Starter
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Talking It all worked out in the end

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Originally Posted by Dave in Green View Post
@Browningate , yes, either trade in the projector for a standard throw model to use with that screen or get a new screen that works better with UST projectors. Wide Power is a unique material for front projection that has been variously described as acetate, mylar or acrylic. I believe it was only offered by Da-Lite and there is very little user information available about how it actually performs in home theater use.
Just to follow up, I traded the Epson in for a Dell 1610HD. Very impressive. Not only has this improved geometry and overall PQ dramatically, it also freed up the Epson for a ceiling mount elsewhere. Good win!

Picture shows the projector screen alongside a Sony KD-32FS170 32" 480i direct-view CRT (which makes a great substitute for PiP! )
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post #8 of 9 Old 06-08-2018, 06:32 AM
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Glad to hear you are pleased with what you ended up with. That must be an antique AV store you're dealing with as both the Epson and Dell models you've gotten are 8-year-old WXGA designs. Hopefully you didn't pay a lot as either could easily be outperformed by one of the $500 1080p models available today.
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post #9 of 9 Old 06-08-2018, 07:15 PM - Thread Starter
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Talking My favorite store!

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Originally Posted by Dave in Green View Post
Glad to hear you are pleased with what you ended up with. That must be an antique AV store you're dealing with as both the Epson and Dell models you've gotten are 8-year-old WXGA designs. Hopefully you didn't pay a lot as either could easily be outperformed by one of the $500 1080p models available today.
It's an excellent AV store called Craiglist.
The Dell set me back a whole $80, as did the screen, and the Epson about half that.
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