# 3D Movie Screens and Strong MDICinema



## coolsvens (Jul 24, 2013)

Hi Everyone,

I am a Technical Director and we are looking to get a new movie screen capable of handling passive 3D for Front Projection only. As everyone knows Movie Screens are not that cheap. I am looking for a screen 20'H by 36'W to fit in our proscenium. I have gotten a few quotes back from some of the major manufacturers (Stewart and Da-lite) and the cost of the frame and screen material has been in the $30K-45K range. Stewart being more expensive as they are the only ones that can provide a non-seamed screen the size I need. I was told about a company in Canada that is suppose to be very good called Strong MDICinema. They got back to me with a quote for a frame and screen for only $10K, and based on the specs it has a better screen Gain than the other manufacturers. It just seemed like it was too good of a deal to be true. I was wondering if anyone else has used Strong MDICinema or can speak about the quality of their product. One thing I know is, the screen will require some welded pvc seams, but this shouldn't be an issue once the screen is front light. The MDI Screen material they speced is the Stereo3D which has a 2.2 gain. Any suggestions, help or insight to why the price is so reasonable would be a great help.


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## ruinexplorer (Jul 24, 2013)

First off, I'd make sure that there wasn't a mistake in the quote which dropped the price (such as size). I would also check to see what the frame is going to be made from. I am assuming that the other two will be giving you something that can be easily struck (if need be) or can handle theatrical elements (I know of a theater that uses a lot of pyro and atmospherics that has a Stewart screen which is still really nice). Stewart is prepared for live events with their large screens. I trust Da-lite and others for their fast-fold or installed screens. My guess at looking at their website, is that they are intended to be permanently mounted (they are cinema screens after all) and not intended for temporary settings as in a live theater. Also, with the higher gain comes a narrower viewing angle. This is part of the problem for doing 3D in a live theater venue in that you will have to limit where your audience sits. The high gain is necessary due to the polarizing filters dropping the foot-lamberts to a much lower level than a comparable 2D presentation with the same projector.


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## coolsvens (Jul 25, 2013)

Thanks for the insight. The screen size is correct based on the square footage they sent in the quote and the diagram. I will check and find out about it being more of a permanently mounted screen. I will admit the thickness of the frame is less than I had expected. It is about 2", but it does have support hooks to rig it to fly. Da-Lite can't handle the size screen I need in the 3D Material. Stewart can, but is very expensive. I am also a little torn with what gain to get, the reason being that we have an extremly bright projector and short throw distance for our space. It's a 24.5K Lumen projector and only throwing 75' to the screen. Based on what the projector's normal size screen and distance, I imagine it's going to be a bright image, and maybe that means I can get away with a lower gain screen for 3D? Thought?


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## ruinexplorer (Jul 25, 2013)

I will agree that you have a very bright projector for 2D presentation. With a screen gain of 1, you would end up with about 34 foot-lamberts for a 2D presentation. I don't remember off the top of my head what the theatrical standard is (I think it is 16), but I would venture to say that you could look at getting a lower gain screen in order to maximize viewing angle and contrast. However, with a typical 3D setup, you could loose 80% of your brightness, or about 6.8 foot-lamberts at the screen gain of 1. This is slightly higher than the average in many cinemas around the country which end up around a 4, but it will still appear dark. As to which screen you should go with, I cannot offer any experience as I have never purchased a screen with the intent of showing 3D. I have only used 3D in corporate events with less than cinematic appeal (one was an open heart surgery).


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## museav (Jul 25, 2013)

I believe the DCI standard for image brightness is 14ftL (+/-3ftL) but those standards also define very low ambient light levels that allow for the desired image contrast ratio with that low of a image brightness. If your ambient light levels are higher than those defined then you may want a correspondingly brighter image in order to maintain the same image contrast.

Your projector may be rated at 24.5k lumens but that rating is probably with a 'standard' lens at optimal conditions and a new lamp. With a different lens, different zoom and lamp with some hours on it the actual output might be considerably less. FWIW, as long as you are looking at the same image size then the throw distance does not have a direct impact on the image brightness, however it can have an indirect imact through the affect of the associated lens and zoom required for the throw distance onf the projector output. 

Possibly also a related factor, 20'x36' is a 1.8:1 format, so very close to the 1.78:1 format of 16:9. If your projector is native 16:9 format then almost all of the potential projector output will be available for the 20'x36' image, however if the projector is native 16:10 or 4:3 then you'll actually have to create an image larger than 20'x36' in order to support the desired viewable 20'x36' image. For example, a 4:3 projector would have to create a 27'x36' overall image or a 16:10 projector a 22.5'x36' overall imag order to provide 20'x36' viewable image and the projector output would be distributed across the larger overall image, not just the viewable portion.

http://www.google.com/url?sa=t&rct=...KXJV9z1aq3I2QN1pZZxizsA&bvm=bv.49784469,d.eWU is a very good presentation on 2D and 3D digital cinema screens as well as Harkness Hall possibly being another manufacturer to consider.

On the quotes, you might want to verify what is included in terms of not only the frame or truss but also masking and any other options as well as practical issues such as whether the price quoted includes shipping and taxes.


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## gafftaper (Jul 28, 2013)

I think I would call Strong and say, your bid came back so much lower than the competing bids that I want to go through it and make sure there are no errors. Then go through the whole thing with them making sure nothing is missing and trying to figure out what corners they cut.

EDIT: You might also ask them if they can give you some references for places they have installed their screens.


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