Is my math correct for a 2.35 1 screen? - AVS Forum
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post #1 of 16 Old 05-13-2010, 06:08 PM - Thread Starter
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So, does this sound right for a 2.35:1 screen? I think it is, but I wanna check before I cut.

118" wide x 50" tall = 128" diagonal, correct?

Thanks!
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post #2 of 16 Old 05-13-2010, 09:35 PM
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The diagonal is approximately 128.156
118x50 turns out to be 2.36. If you are set on having a width of 118 then your height should be 50.2128 or if you keep the height constant than your width should be 117.5. I would go with the later due to 117.5x50 works better in the imperial system. This turns out to be 9.83333 x 4.16667 feet. I'm not sure if you want to build this out of a single piece or not, your room and speaker placement, and especially your masking. Please elaborate.
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post #3 of 16 Old 05-14-2010, 03:55 PM - Thread Starter
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Going to make a frame w/ 1x3s. Likey going to use Seymore Center Stage material, 2" black velvet border. I think I will go with 117.5". Thanks!
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post #4 of 16 Old 05-24-2010, 02:26 AM
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allisgreen, thanks for the explanation.
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post #5 of 16 Old 07-04-2010, 10:35 PM
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BTW, WilsonArt Designer White (gain =1.3) laminate (thin) comes in single sheet sizes up to 12' long (12' x 5' is one available size). One of the AVS members (Studio2000) built a 134" x 57" (145.6" diagonal). screen from a single sheet.

allisgreen -- You always want to use a single sheet. The seam likely will show if you use two pieces.

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post #6 of 16 Old 07-09-2010, 01:31 PM
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Quote:
Originally Posted by seedubxj View Post

Going to make a frame w/ 1x3s. Likey going to use Seymore Center Stage material, 2" black velvet border. I think I will go with 117.5". Thanks!

Just an FYI, I goofed when I made mine. I made the frame (for my SMX material) exactly 2.35:1, and then planned to add a border. But what I forgot to account for was that 4" (in my case) of the top and bottom is a lot more, proportion wise, than 4" off the sides. With a little finagling and uneven placement of my border I ended up with a 2.39:1 screen area, which worked out perfect for me.

But to put it really short, plan your screen area, and then remember to add 2" (or whatever your border is) to each side, rather than figuring your frame and assuming the AR will still be right when you subtract off the border.

Just an example, with your 118x50.25" screen, with a 2" border you'd want a 122x54.25" frame built (which is 2.25:1). If you goof like I did, and don't have the room to offset the border top/bottom, you'll end up with a 114x46.25" screen area (which is 2.46:1).

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post #7 of 16 Old 07-09-2010, 07:05 PM
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Also, if you end up using the Center Stage XD, I would highly suggest paying the extra money for grommets to be added. It cost more $, but it will save you headaches when it comes to getting the screen tight. You can check out my XD screen if you're wanting some tips or ideas on it. I love the material, well worth it.

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post #8 of 16 Old 07-10-2010, 04:52 PM
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Quote:
Originally Posted by seedubxj View Post

So, does this sound right for a 2.35:1 screen? I think it is, but I wanna check before I cut.

118" wide x 50" tall = 128" diagonal, correct?

Thanks!

Glad someone else gave you the information.........

I was preparing a lesson in "Pythagorean's Therom" or for those who are more abstract......"Law of Cosines"
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post #9 of 16 Old 07-11-2010, 12:33 AM
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It's actually quite simple. Width = 2.35 x height. Then, as stanger89 pointed out, you add the width of the border to the top, sides, and bottom, to get the overall dimensions of the screen frame. The screen material should be almost as large (or equal, or larger) than the frame, depending on what material you use and how it is attached.

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post #10 of 16 Old 01-29-2011, 11:56 AM
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Is it "better" to make a screen 2.35:1 or 2.40:1?
I ask because I've read somewhere that if a film is 2.4 you'll still get slight borders with a 2.35 screen but on a 2.4 screen showing a 2.35 film you wont?
I know so little about this I dont even know what I dont know, so please excuse my ignorance.Where would a slight zoom come into it to solve this?

I've just bought my first PJ JVC 350 (europe) and very excited to see what Ive been missing. When it comes to screens and lenses though I want to get things right first time.

Thanks for any opinions

PS been lurking a while and feel very informed by all of you. Thanks a lot!
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post #11 of 16 Old 04-26-2011, 07:11 PM
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Quote:
Originally Posted by bigjas View Post

Is it "better" to make a screen 2.35:1 or 2.40:1?
I ask because I've read somewhere that if a film is 2.4 you'll still get slight borders with a 2.35 screen but on a 2.4 screen showing a 2.35 film you wont?
I know so little about this I dont even know what I dont know, so please excuse my ignorance.Where would a slight zoom come into it to solve this?

I've just bought my first PJ JVC 350 (europe) and very excited to see what Ive been missing. When it comes to screens and lenses though I want to get things right first time.

Thanks for any opinions

PS been lurking a while and feel very informed by all of you. Thanks a lot!

I would also like to know this...
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post #12 of 16 Old 05-27-2011, 08:07 PM
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+1

Just starting to research screen sizes for my planned room, and I'm curious about the benefit of 2.35 vs 2.4 as well

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post #13 of 16 Old 05-28-2011, 07:16 AM
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Quote:
Originally Posted by J_P_A View Post

+1

Just starting to research screen sizes for my planned room, and I'm curious about the benefit of 2.35 vs 2.4 as well

My screen is 2.37:1. If I was to make another screen, I might go for the slightly wider 2.40:1. The reason is this: The letter boxing on video (DVD and BD) makes the format CIW for anything over 1.78:1. So the difference between 2.35 and 2.40 is now in the image height (active picture only), not the width.

So even after scaling, a 2.40:1 image will have slivers of black bars top and bottom. To rid the slivers of black, you can always apply a slight amount of zoom and of course 2.40 now becomes wider than 2.35 on a true CIH system.

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post #14 of 16 Old 05-28-2011, 07:18 AM
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Quote:
Originally Posted by CAVX View Post

My screen is 2.37:1. If I was to make another screen, I might go for the slightly wider 2.40:1. The reason is this: The letter boxing on video (DVD and BD) makes the format CIW for anything over 1.78:1. So the difference between 2.35 and 2.40 is now in the image height (active picture only), not the width.

So even after scaling, a 2.40:1 image will have slivers of black bars top and bottom. To rid the slivers of black, you can always apply a slight amount of zoom and of course 2.40 now becomes wider than 2.35 on a true CIH system.

I agree. I went with a 2.40 AR screen and no matter what the AR is of the movie I'm watching, I never have any slivers of black bars on top and bottom.
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post #15 of 16 Old 05-30-2011, 06:00 AM
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I find having the slight pillars at the side of a 2.35:1 film far less offensive than the slivers for a 2.40:1 film.

Mark Techer

I love my Constant Image Height system!
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post #16 of 16 Old 05-30-2011, 06:08 AM
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Quote:
Originally Posted by CAVX View Post

I find having the slight pillars at the side of a 2.35:1 film far less offensive than the slivers for a 2.40:1 film.

I agree 100%
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