Home Theatre 3D Stereoscopic Projection + DIY Silver Screen

[ignatius]

Hey all,

http://www.stereoscopic3dmovies.com has some great 3D movies in blu-ray and dvd, plus awesome deals on 3dtv's.

I was wondering if there are any experienced members in this forum who have built their own home theatre setup for 3D stereoscopic content using the passive polarization method. There were a few things I could use some help with. Before posting this message I had researched all over the internet, in this forum, googling, the works but I could not find the answers or I should say the right 'materials' I need to build this home theatre. I have come across this thread, http://mtbs3d.com/phpBB/viewtopic.php?t=509" onclick="window.open(this.href);return false; and found it very informative and helpful. But it's slightly different than the setup I'm building. Mainly because I have to build the silver screen. This is going to be a long post so I hope people don't mind reading a lot.

I'm building my first home theatre 3D stereoscopic projection room. I will be getting a couple of Optoma HD7100 projectors. There is a review of it here, http://www.projectorreviews.com/optoma/hd7100/" onclick="window.open(this.href);return false;. I will use them with 2 linear polarized filters in front of the projector lens that will be projected onto a 140" (diagonal) silver screen with a pair of linear polarized glasses that you wear to watch the 3D content. This theatre room will be in a light controlled dark room. I've researched about the differences between the linear and circular polarizer's but the differences are very small in terms of 3D quality and the price in comparison is huge. So I will be sticking with the linear polarization method for now and maybe upgrade to circular in the future.

Before going on I would like to mention that this whole setup is for the average joe, a poor-man's theatre room, and a do-it-yourself as much as you can to save some bucks project. So the goal is really to find the best and cheapest material to get almost similar (or hopefully identical/superior) results from professional products.

One of the issues I have are finding the best polarizer materials for the filter and 3D glasses that is made of great quality and is relatively cheap. The goal is to achieve as little ghosting as possible. There were a number of online stores I found that sell cheap polarizer material. Here are a few:

http://polarization.com/" onclick="window.open(this.href);return false;
http://www.3dstereo.com/viewmaster/pj-pfilt-3x3.html" onclick="window.open(this.href);return false;
http://www.3dlens.com/shop/polarizer.php" onclick="window.open(this.href);return false;
http://www.berezin.com/3d/3dglasses.htm#Polarized" onclick="window.open(this.href);return false;
http://www.studio3d.com/pages/store.html" onclick="window.open(this.href);return false;

Does anyone have any experience with any of these online stores and can comment on the quality of their polarizer products? Another solution I found on the net was to buy polarizer filters that are used with photo cameras. I found this solution here, http://www.scec.org/geowall/filters.html" onclick="window.open(this.href);return false;. In trying to achieve the best possible quality and the least amount of ghosting (cross-talk) when viewing 3D content. Which polarizer would be the best? The filters that are used for photo cameras? Or from one of the links above? I read that if you use different polarizer's for the filters then the ones used on the 3D glasses, that this will add to the ghosting effect. So if this is true, this would mean that using the filters used for camera lens wouldn't be the best idea, because the polarizer on the 3D glasses would be different. Someone can correct me if I'm wrong.

The other issue is building your own silver screen for 3D. I don't have the budget to spend $300-1000 on a readymade silver screen from professional companies. The best solution and possibly the cheapest depending on the size of your screen if you were to buy a professional made product was the 'Ultra Silver 3D' paint from Goosystems (http://www.goosystems.com" onclick="window.open(this.href);return false;). This product looks great and seems to work really well. But it's still a few hundred too expensive for me. Just for the sake of this thread I will post up some places where you can buy readymade professional silver screens for anyone who does have the money to spend on it.

http://www.paintonscreen.com/index.html" onclick="window.open(this.href);return false;
http://www.silverfabric3d.de/html/sf_silver3d.htm" onclick="window.open(this.href);return false;
http://www.lighthouseprojection.com/index.html" onclick="window.open(this.href);return false;
http://www.berezin.com/3d/screens.htm" onclick="window.open(this.href);return false;
http://t-works.en.ecplaza.net/product.asp" onclick="window.open(this.href);return false;
http://www.stewartfilm.com/" onclick="window.open(this.href);return false;
http://www.harkness-screens.us/ss_3d_spectral240.htm" onclick="window.open(this.href);return false;
http://www.dalite.com/" onclick="window.open(this.href);return false;

I came across two extremely helpful and inspiring links on the internet about building your own 3D projector and silver screen from scratch.

http://www.lumenlab.com/forums/index.ph ... ode=linear" onclick="window.open(this.href);return false;
http://www.allinbox.com/vp3d/vp3d.htm" onclick="window.open(this.href);return false; (in French, use babelfish to translate)

They did a great job explaining everything in detail. One of them painted their wall to use as a silver screen and the other used a special silver fabric. The best type of paint to use for a silver screen is apparently a white metallic paint, or essentially any kind of metal paint which have polarization properties. Another tip I found was to use a matte paint over the silver screen to get rid of most or all of the unwanted bright hotspots. But would this effect the polarization of the screen? You can even use silver aerosol paint spray cans to make the silver screen with decent results. Another person on the internet (forgot where) mentioned he used silver nylon used to cover vehicles that seemed to have worked very well. I have not been able to confirm any of this myself yet, just simply reading what other people have done with some results.

I have yet to experiment all the different types of silver paints/fabrics to find the best one to use as a silver screen for 3D. I was hoping there would be someone on the forum who could point us to a specific kind of paint or fabric that they have used that seems to work really well with minimal to zero ghosting. That they can find in your local hardware/paint/fabric store.

I would really appreciate any kind of help that anyone can offer on this topic/project. I will continue to post my own progress with building my home theatre 3D setup and will post any useful information I may come across or find.

http://www.stereoscopic3dmovies.com has some great 3D movies in blu-ray and dvd, plus awesome deals on 3dtv's.

Cheers,
Varinder

[Tril]

I don't think it will be bright enough at 1000 lumens with a diagonal size of 140". I've got an Optoma HD71 that's rated at 2400 lumens, a silver screen, a distance that gives me a screen size of about 100" and a polarizing filter. With the filter on, it's just the perfect brightness. I also have an Optoma EP739 that's rated 1700 lumens in eco mode. On the same screen at the same distance with the same filter, that second projector is not bright enough. Everything turns very dark. Details that are clearly visible with the HD71 become invisible with the EP739 because everything that's close to grey/black is seen as black.

If you want to go cheap on the filters, you can buy some sheet polarizer for about 30$ at Edmund Optics and cut it to the size and shape of your choice.
If you want to go more expensive, you could order a pair of polarizing filters laminated between glass with anti-reflective coating that are 4"x4" (or bigger) from API American Polarizers for around 150$. I'm suggesting them because I ordered a pair of filters from them. They are of good quality.

About photo cameras, you risk burning them (I haven't tried them so I can't confirm if this is likely to happen). If the filters get too hot, they break. I've had that happen when I tried to use some very cheap polarizing glasses theme park style as a temporary filter while testing the projector.

A word of warning about making you own screen. You can succeed or you can fail. If you fail, that's wasted money. If you use aerosol cans, you will most probably not be able to do a clean job. If you use a roller, it will be very hard to make a screen without texture. Your best bet is to use a spray gun but you'll need to buy one and that adds to the cost. I tried to make my own screen and in the end, I failed. I tried to use cans and it turned out ugly (visible circles, streaks). I then tried to use a roller but it left a visible texture and I messed up the choice of paint so it did not preserve polarization enough. It's not impossible to make a screen but if you're an average painter, you might fail on your first try. You might also have difficulty finding the perfect paint. You need a metallic paint but you need to find one that does not sparkle too much. Since it's to put indoor, you need a paint that won't smell for a long time.

I also made my own screen out of wood. The design is bad and the wood is showing through the fabric. I could post some pictures, to give ideas about what not to do.

I tried a few different paints and painted small canvas (about 12"x10") to test on samples of the paints. I could try to find those samples tell you which ones seem likely to work, which sparkle too much and which don't work at all. I think I still have that somewhere.

I could also take pictures of my homemade projector holder and post them.

You could buy cheapers projectors and buy a screen.

[ignatius]

Hey Tril,

Thanks for the feedback. I would love to see the pictures you took of your experiments if you don't mind sharing them. It's too bad you were unsuccessful in building your own silver screen. I had a good feeling that using aerosol cans wouldn't work well. Somebody had mentioned that somewhere else and said he got decent results with it. But i don't think i would be satisfied with the results myself. But i will still give it a try. You are right that it is best to spray paint a silver screen instead of rolling. Rolling would shoot the polarized light off into the wrong direction, whereby spraying the silver screen the polarized light is projected back to the viewer properly. There was a site that explained this perfectly specifically for painting silver screens for 3D, I will try and find it.

I have read that if you use a metallic paint and finish off with a matte, it will reduce the amount shine and hotspot without losing any of the polarization properties. So, I hope this is true once I try it out for myself.

Thanks for showing me those links for the polarizer filters. I won't be spending too much on the filters right now, maybe in the future. So I'll be looking for cheaper but good quality polarizers like the one from Edmund Optics. Did you try these ones out as well? How do they compare with the ones from API?

I've also read about polarizer filters heating up and melting or even cracking due to the heat from the projector. But it seems that Jahun from, http://www.mtbs3d.com/phpBB/viewtopic.php?f=26&t=509" onclick="window.open(this.href);return false; is using polarized filters used for photo cameras and rates them as superior for 3D. This is one reason why I'm stalling to buy cheaper polarized sheets when I can buy well made optical polarizer filters that have 'superior' quality. Maybe Jahun can comment on this.

I did quite a lot of research on which projector to get, not only for 3D viewing but as well as 2D viewing. And after that extensive research, I found that the specs the companies write down about their projectors are always quite wrong. Even though the specs say the HD7100 only has 1000 lumens, it's been reviewed and noted many times how bright this projector really is. So, I'm not too worried about that. I've also reviewed your HD71 and that projector is very bright and probably awesome for 3D, too bad you don't have two of them .

Again, it's too bad your DIY silver screen never worked out. I'm still interested in seeing your pictures. But I'm really hoping I can find a cheap solution with some great results with minimal ghosting. I'm prepared to do quite a bit of testing and I will post up my progress.

Cheers,
Varinder

[sharky]

here is my setup.. its quite expensive but it works great and you will be satisfied since its almost the top you can have for home cinema.

projector:

2x hitachi CPX5 LCD 2400 lumen 90° output angle (very good for small rooms) ---> 702 euro each

filters:

2x SPAR filters ----> 540 euro each

silverscreen:

2x1,8 meters -----> 400 euro

glasses:

linear polarized ----> 4 euro each

this is all without shipment and vat. the prices are all quite old except the projectors wich include vat. all the other prices are from may more or less.

again, only a high quality setup gives a high quality result.. i think tril, likay and others can confrim since they all went for a good setup at the end..

[Tril]

Not completely for me. My initial plan was to use two EP739 bought cheap because they were recertified. I bought two but one of them broke just after the end of the warranty and just before I got my screen. After that I bought the HD71. I tried to use the two together but the EP739 is holding back the other projector too much. I have to turn down dramatically the brightness on the new projector if I want to use them together. I can use them together if I want and I tried it once before but I don't do it anymore. It's not bright enough and I prefer a setup that's always ready to use without any setup time. That's why I got an iZ3D monitor.

[Likay]

I can confirm Sharky's impression about a passive rig. It's convenient because everybody who wants to watch only needs a couple of polarized "sunglasses". Iz3d stylish ones works good but those dorky themepark ones have better ghostingrejection. The difference isn't too big though. Myself i use clip-ons because i use ordinary glasses.
The rig: 2000x1500mm 100" silverscreen from silverfabric (now awater3d), stereopol filters designed for lcd-projectors with 75% light throughput (SPARS as Sharky have) and two hitachi cp-x260 2500 lumen.
I always run the projectors on low noise setting (2000 lumen) and the 100" screen is still as bright as a normal lcd-screen! Wish i had room for a bigger screen since there's plenty of light for it.
Regarding ghosting rejection i've compared my rig with the one in the themepark "Liseberg" in Sweden. There's also an imax in Stockholm (cosmonova) but i haven't checked it. The ghosting rejection is better with my silverscreen than the screen in the Liseberg themepark. That screen has a special design though: It's made of metal and in a sort of "beecake" pattern (full of holes in it). Probably to let sound through or something. This could be very well be the cause of a slightly worse ghostingexperience. I don't know if every imax cinema uses such screens.
If someone wants to try passive polarization (you have two projectors) you can try buying some cheap rustpaint as mentioned in some thread and simply use ordinary polarizerfilms. If you don't have polarized films you can find it in trashed lcd-monitors or order from polarization.com. Beware that you're still are going to need some amount of light. With standard polarizers you'll have a maximum of 45% light throughput through the polarizer! The special SPARS-filters have a lightthroughput of 75% but works ONLY with LCD-projectors!. If i'm not wrong Sharky's filters might have even better values than the ones i have.
One other big advantage with passive rigs is that you need two standard left/right signals for it. And almost all stereoscopic softwares supports that natively. In these times it's priceless!

Relativity of lightexperience with different projectorsetups:
With dlp-projector and shutterglasses you have maximum 22.5% light throughput to each eye! This is because the internal polarization of shutters (shutterglasses uses lcd-crystals in combination with polarizing foil) efficiently steals 55% of the light and both eyes have to share the rest.
Dual projectors with standard polarization foils have 45% light throughput. Since each eye have it's own projector the lightexperience is doubled compared to shutter/dlp.
Dual LCD's with stereopol filters have a lightthroughput of 75% to each eye! Gaming with 2x2000 lumen on 100" in fully daylight causes no problem. Thought it's nicer if everything is lit out so the screen almost totally disappears!

Backsides with passive projection: Expensive. Parts are expensive. Projectorbulbs arent cheap either.
Projectoralignment is said to be a backdraw but if you ask me it's part of the sport. Once when learnt the important things with aligning the zoom/keystone and by using a testpattern made for this purpose it takes 5 minutes to get it right! The rig is sort of "portable" and i have used it at a few other places than my home.
Another drawback is simply projectorusage. It's not healthy for the lamps turning them on and off often for small amount of times.
For this i have an iz3d for occasional gaming.
Some says passive rigs ghosts... Well: It ghosts more than a dlp/shuttersetup but the ghosting with a passive rig causes no problem even with very high contrasts. So as i see it it's no problem and no use chasing higher numbers for ghosting rejection. The big point of passive rigs are that it's simplicity for use when several people are looking and most of all the light emitted to the eyes.
For me building the rig was like fulfilling a dream. I gamed with shutterglasses/crt by the time and was really interested in going a "shutterless" system way. I had great plans in building a planar polarized rig but a visit in that themepark had me on other ideas.

[ignatius]

Hey guys,

Thank you so much for the feedback, really appreciate it.

Unfortunately i can't buy an lcd projector and purchase the very expensive SPAR filters it seems to go way over budget. However, this setup I'm building at the moment is a temporary one and I will only be keeping it for maybe a year or so. Afterwords, I will be upgrading once again to a pair of 1080p projectors or possibly a single 1080p projector that can project 3D images. Or a pair of LCD projectors using the SPAR filters if there still rated as one of the best methods for viewing 3D in passive polarization. The year of 2009 is going to be a great year for 3D and I'm aware of a lot of different companies and new displays coming out. So i'm guessing in a year there's going to be a lot of great 3D displays to choose from.

But for now, I'm just going to settle with dual 720p's using dlp projector and if i can get even reasonably good 3D effect using the passive/polarized method with a DIY silver screen. That would be more than enough for now. If the shutter glasses are able to show 0% ghosting, I would be happy with a projector display that even displayed 20% of ghosting compared to the shutter glasses.

At the moment, I bought a number of different silver materials, paints and fabrics to test out. Since i don't have the 2 projectors yet or any proper polarized filters. The way I am testing out the quality of the silver material. Is by pointing a flashlight through one of the polarized glasses i have (i have both circular and linear 3D glasses on hand) and pointing it at the silver material and then seeing the effect with another pair of polarized glasses to see how well the extinction level is works with the silver material.

I have a question though, since i'm not sure how well this method works for testing ghosting and extinction for polarization. But how black or opaque should the 3D glasses be when the light comes back from the silver screen? Should it be almost completely dark or is it ok for a little light to pass through?

Cheers,
Varinder.

[ignatius]

I've also just recently found a very good cheap projector that is better than the Optoma HD7100. But the only downside is that it has no lens shift. It has the digital lens shift, but i heard that's terrible.

Sharp XV-Z3000 -http://www.projectorcentral.com/sharp_z3000.htm
or
Optoma HD7100 - http://www.projectorreviews.com/optoma/hd7100/" onclick="window.open(this.href);return false;

Should i sacrifice quality for lens shift capabilities? Is aligning the two projectors really that big of a hassle?

Would appreciate anyones suggestions.

Thanks,
Varinder

[Tril]

I have experience with aligning an Optoma EP739 with an Optoma HD71. They both don't have lense shift. I use the projector holder I made to align the projectors. I leave the digital keystone adjustment off on both projectors. There is a slight keystone effect but it's small enough that it does not matter. I usually used the text of the icons on the desktop while I set the video card to clone mode as a guide to align the projectors. It might be better to use a test pattern instead but I did not bother finding or making one.

One thing that you have to take into account with projectors without lense shift is that when projecting from a high position, they are made to be hanged upside down from the ceiling. If you want to place them on a shelf high up, you'll have to place them upside down and you won't have access to the buttons on them. That's when the remote control comes in handy but since you have two identical projectors, it's a bit impractical (if you want to change the settings of only one of the two) as they will both respond at the same time.

[Likay]

I don't have lenseshift on my beamers so i have to, and uses digital keystone correction on my projectors. There's not a big deal of "pixellines" because of this but i run the games in native 1280x960 when the projectors native is 1024x768. This makes any rests disapear though.
To minimize the keystone phenomena you should mount the projectors as close to each other as possible. Have chilling of the projectors in mind so you don't interfere with that!

If you don't use keystone correction the image shown from the screen looks diagonally curved, like a bent sheet. It's no big issue and in the beginning i actually thought the effect was cool! The effect is less when you turn on 3d though.
I would definitely say that usage of keystone better that being without though. Lenseshift is the best since you're able to use the projectors native resolution (sharper picture) but might take more time to get right depending on how easy it is to adjust.

If you want to try different materials regarding preserving polarization the best thing is trying to project an image with polarized light on it and you'll also see how it actually looks like.

[ignatius]

Hey guys,

Thanks for the feedback once again. I'm glad not having a lens shift option with the projector doesn't seem to be that big of a deal. But a few experts with projectors still preferred the HD7100 over the Z3000 projector (for 2D viewing). So, I guess I'll still have my lens shift capabilities if I go with the HD7100.

After working on a lot of 3D content, I've also learned that the keystone effect is a major NO-NO when it comes to 3D. So I will be trying my best to avoid the keystone effect while projecting the images.

I'll also give an update on my progress with creating my own DIY silver screen. Even though i still do not own dual projectors and proper polarizer filters to accurately determine the quality of the polarization properties of the silver materials I have been testing. Using 2 linear or circular polarized 3D glasses seems to be doing a pretty good job at detecting the amount of polarization/extinction level of the silver materials.

I have yet to test out a couple of metallic aluminum paints i bought. But I did buy a number of silver reflective fabrics to try out from a bunch of local fabric stores. Using my very simple 3D tests, the results were quite surprising and I learned a few things that may or may not have been so obvious.

Out of all of the silver fabrics I found, the ones that showed the best results were the ones that were very flat and had no textures. I will have to go back to the fabric stores and ask them what this type of material is called and let everyone know. But the closest description i can give is that it's sort of feels like leather, except it doesn't have that rough surface instead it's incredibly smooth and flat. Surprisingly enough these fabrics didn't seem to produce a very SHINY effect either, it had a very matte look to it. So that's a major plus. And because it was nice and flat with no textures, that's another plus when it comes to projecting images onto this screen because there won't be any 'noise' coming from the silver fabric onto the image which would be incredibly distracting. I will take some photos of the materials I'm testing as well as their specific names so people won't have to go through all this trial and error. Or at least they can have a good start when making their own DIY silver screen. I'll post those up soon I hope.

I'm testing out the paints I bought right now and I will let you guys know how that went. There's one particular silver paint i got which is made by a company called Rusto-Leum (Tremclad) and it's an Aluminum rust paint. I've read at a number of different places on the net and a lot of people seem to have had very good results with this. One person in particular wrote down a very descriptive method of applying this paint that you can find here.

http://tech.groups.yahoo.com/group/phot ... sage/53419" onclick="window.open(this.href);return false; (you may need to create an account to see the thread)

If someone doesn't mind doing a small test for me to determine how well their silver screen works by the method I'm using right now. That would be super helpful. All i'm doing is grabbing a pair of 3D glasses and holding a flash light behind it, and wearing the other pair of glasses and I simply rotating the 3D glasses in my hand to see how much the light is getting blocked with the polarized glasses. I tested this in a pitch black room to get the best results. I'm very curious how well this method works or not. If i were to rate the amount of light that gets blocked in one of the lenses with my best fabric, it's probably about 80-90%. I think that's pretty damn good with a piece of fabric found at some local fabric store. However, I have no idea how valid this method is in determining the effectiveness of the silver material. Not only that, but i can't even see what kind of negative or positive effect this may have on the image itself. Hopefully someone with any experience comment on this.

I hope to get a couple of dual projectors and proper polarized filters to test out the silver material properly with a 3D image. But for now, this is the best i can do.

Cheers, and sorry for the long post.
- Varinder

[Likay]

According to your test: I found an old thread about ghosting on different rigs:
http://www.mtbs3d.com/phpBB/viewtopic.p ... 1&start=20" onclick="window.open(this.href);return false;
This is with the rig i have.

[ignatius]

Hey likay,

Thanks for showing me that link. Looking at your screenshots on that thread, if that's the amount of ghosting you see that's really good. That was projected on the silverfabric using the SPAR filters correct?

I'm so curious how much worse the silver fabric's i found and some cheaper filters would compare to your setup. Even if it were slightly worse, I'd be a happy duck.

-V

[Likay]

Hi!
Yes: That is/were what i'm using.
As said: When ghosting is down at this slight amount there is no actual reason trying to push it down any lower. Ghosting rejection should be better with active good dlp-projector+a good pair of shutters. However: Shutterglasses are never ghostless either! To have similar light as from a passive rig from a single projector with shutters require an really strong projector and there you blow the economy anyway.

You don't need spar filters (lcd only!) to have this good ghosting rejection! The reason to use spars is mainly to have a brighter experience! Use a couple of high quality polarizers if you want to go cheaper at a start (like those in lcd-monitors if you're able to find trashed ones). Also: Lcd-projectors works great with ordinary polarizers if you plan to eventually upgrade your filters at a later time.

The needed thing for lcd-projectors is that the polarizers need to be aligned at 45° angle as the one the lcd's are having. Unfortunately it's not possible to use lcd's without filters because the colors are aligned differently. For example: If the color red is aligned at 0° the green and blue are aligned at 90°. If you align the polarizer 45° you still get an equal amount of colors (red,blue and green) to the eyes. Therefore lcd's actually works great using standard polarizers as well!

If you aren't using too shitty polarizers ghosting will be caused mostly by the silverscreen! (in other words: The silverscreen is the most crucial part!)
Myself i'm curious of what results are with those paints (screen-goo and aluminium rustpaints) available compared with silverscreens. I haven't tried but these should be very good option for diy's! It's easy to upgrade both to a screen and/or filters later on.

Edit: Linear vs circular polarizers.
I've tried both circular as well as linear polarizers and circular ghosts significantly more than linear. It's not a massive difference but there is.
It's said that circular polarizers/glasses allows you to rotate your head without loosing polarization ratio. This is only true to a certain degree. Circular allows slightly more tilting than linear but don't count on anything more than a few degrees! When playing stereoscopically where the content is rendered in a horisontal axis you need to have your head aligned horisontal as well to preserve correct impression. Try viewing anaglyph or with shutters and you'll see what i mean. Basically i'm trying to explain that being able to tilt you're head more is of no use viewing stereoscopic content without a headtracking device that also registers headtilt.
So: Linear polarizers are more common, easy to get, cheaper and works way better than circular filters. Go linear!

[Tril]

Here's my thread about my attempt at making a passive projection rig : My DIY attempt at building a passive projection rig. I posted the paint tests I did. The results are not very extensive but that should still be a little useful.

The second post is an old post I wrote last year but never posted. It's not up to date but it might still be an interesting read. Since then, I bought a Da-Lite screen.

[ignatius]

Thanks tril!

I read the whole thing and posted a small reply.

Cheers,
Varinder

[wnielsenbb]

I got my cheap plastic polarizers and glasses from Berezin. I got 3D screen material from Harkness-Hall based on reviews. $337 for 120" diagnol and $32 for shipping. I am using an LCD projector, the Panny ae2000U, but due to the smoothscreen filter the special LCD polarizers don't work. The cheap plastic ones do though. I haven't got my second projector yet, so I haven't finished the setup. With all the 3D stuff coming out this year, it is tempting to wait. I have thought about doing Circular polarization. The nice thing about circular polarization is all the free glasses from the theater.
Warren.

[nubie]

There is a nice 100" diagonal 4:3 screen here for $63.48 http://www.provantage.com/da-lite-90618~7DALI094.htm" onclick="window.open(this.href);return false;

I don't know how the old-school da-lite silver matte suits your fancy though.


I did order a Da-Lite once, it shipped from the factory, so even if the site is sketchy you are probably going to get it shipped from the factory.

Those projectors look awesome btw

[ignatius]

Hey guys,

Thanks for posting more info about cheap solutions for building a 3D home theatre and your own experiences.

I'm nearing the end of my whole 3D home theatre project. But I've come across one final problem. The really awesome silver fabric I found that works incredibly well with 3D, has one major downside. It has a really bad hot spot from the light coming from projector. Now, I was thinking of using a clear matte finish on the silver fabric to get rid of the shiny glare. But I'm not sure if this will have a negative effective on the polarization or if it'll create ghosting due to the secondary 'plastic' coating from the matte finish.

Any help or suggestions will be very much appreciated. Thanks.

- Varinder

[wnielsenbb]

Did you try with the polarizers in place (on the projector and the glasses). They will reduce the brightness of the projector which may be enough to eliminate the hotspots. Otherwise you may need an ND2 filter.
Warren.

[Likay]

I've noticed the glare in my rig too. Spotted it first when taking pictures of the screen though.
Don't know any way to deal with it though. It's not a huge problem when gaming since you're mostly focused on the center area of the screen. That makes the phenomena become really less.

[ignatius]

Hey guys,

Thanks for posting back. I don't have proper polarizer filters, I'm just using a pair of 3D glasses at the moment in front of the projector lens. And it doesn't get rid of the hot spot, it's mainly because of the extremely reflective screen I'm using.

But, I went out and bought clear matte spray paint and sprayed it all over the screen and it worked like a charm. The hot spot is gone and it had no negative effect with the image quality or polarization. To be quite honest I wasn't thinking it was going to work, but it ended up working incredibly well. Got rid of the shine and now the screen is nice and matte.

I'm very close to completing this theatre now, just a few more days. I'll be posting up a very big post when its all done with pictures of my completed home theatre and everything I used. I hope this will help others when they start to make their own 3D home theatre solution on a tight budget. I don't think it'll get any cheaper than the route I took.

Cheers,
Varinder

[ignatius]

Hey guys,

This tutorial I wanted to write up is long overdue. I've been side tracked with a lot of other things going on in my life including a 3D film I'm working on. But here it is and I hope this helps people out.

Early on in the year I wanted to build my very own 3D home theatre and there were a few challenges I had to face while trying to build my own 3D theatre. But, after a ton of research and going through the whole process of building one, I finally completed the 3D theatre over a month ago. Aside from the few challenges I faced that can be easily avoided or can be prepared for, it's very easy to make your very own 3D theatre at home.

I was planning to take really cool 3D photos of my whole setup as well as 3D photos of the 3D content the way I see it from where I sit. But I don't have my camera available for that so I will have to upload them next time, hopefully next week sometime. So for now I will have to post up crappy pictures taken with my phone.

[ignatius]

What you need:

2 x Projectors
(I have the Marantz VP8600)
You will need two projectors that are preferably identical in make and model. The main reason that you will want to have two identical projectors is that when you project the images out of the two projectors that the colors, the brightness, contrast, etc are the exact same. That way each eye is getting the same information. When each eye is seeing something different, like the colors, one projector is brighter or darker than the other. This will produce headaches for the viewer and the 3D image will look wrong.

How many Lumens do you need? The higher the better of course, but what would be a high amount of lumens? Well, let me mention that the projectors I have are only 800 lumens. Now that seems pretty damn low right. But, after I did an intense amount of research on projectors. I realized that the amount of lumens that most if not all projectors out there state they have are quite a bit exaggerated. So, I prefer not to even look at how many lumens a particular projector has. The best thing you can do is check out as many reviews on a projector you are interested in and see what people say about the brightness level. Let me tell you that the 800 lumens my projector can kick out is pretty damn bright and I'm very pleased with the results. But again, everyone will have their own personal preference. So what I think is bright, might not be bright enough for some. So always take that into consideration when checking out reviews.

There is one important factor you should keep in mind when choosing a projector for 3D. When you are using the passive stereo method, it's hard to determine how much light you'll be losing exactly but it's safe to bet around 50% of the light coming out of your projector when it travels through a polarized filter, bounces off a silver screen and going through another polarized filter that you'll be wearing, the 3D glasses. So for 3D, brightness and lumens pay a much more important role than they normally would for 2D viewing.

DLP or LCD? Once again, it comes down to personal preference. DLP's to me have nice contrast and vivid colors, while LCD's offer a huge amount of lumens and brightness. There is a huge advantage and disadvantage with LCD projectors when it comes to 3D. The disadvantage is that some lcd projectors may not work with a passive stereo method. Because some lcd projectors use some kind of polarization mechanism to direct the light out of the projector and this will have a negative effect on the polarization setup for 3D. However, one major advantage lcd projectors have is that if you do find an lcd projector that works with the passive stereo method. If money is no issue, you can buy these fairly expensive polarized filters called StereoPol filters (or SPARS) that allow a lot more light to pass through which would allow for a much brighter image. Compared to regular polarized filters, you will only lose around 25% of the light. Money was an issue for me and I did not know which lcd projectors would work with the passive polarization method so I opted for a DLP projector. Also because I prefer nicer contrast and colors over brightness/lumens, others may prefer it the other way around.

A huge bonus that will save you a lot of trouble when aligning both of your projectors so each image is perfectly on top of each other when its projected on the silver screen. Look for a projector that can do both vertical and horizontal lens shift that physically/mechanically moves the lens. This will help you out a lot and you won't have any keystone issues when aligning the two projectors. Try to avoid using the digital keystone correction or digital lens shift. Just avoid anything that you can 'digitally' change from the menu on your projector. This will contribute to weird artifacts in your image which will make your 3D look wrong as well as giving you possible headaches.

[ignatius]

1 x Silver Screen
(The name of the silver fabric I found is called "Monroe" used over polyurethane.)
The second most important thing to consider once you've chosen your projectors is the silver screen you need to have to project the image on to. Why a silver screen rather than a normal white or grey screen? In order for the two images being projected by the two projectors to go into the correct eye, we need to direct the light to where we want it to go using polarization. Normal white and grey screens do not have any (or very little) 'polarization properties' on the screen. So when you project the images out of the projectors through the polarized filters and you project it at the white or grey screen. The polarized light information won't be able to bounce off the screen and enter through the 3D glasses you'll be wearing and you won't see the 3D effect. What you'll end up seeing is a double-image on the screen. Silver screens retain the polarization properties of the light as it hits the screen and bounces the light to the correct eye letting you see a 3D image.

The higher the polarization properties on the silver screen, the lower the chance of seeing any 'ghosting-effect' also known as 'cross-talk'. The ghosting-effect is when you see both the images when you're watching something in 3D, I'm sure you've noticed this at times during a 3d film. The reason this happens is because, the information that was supposed to only go into your left eye for example, is leaking a bit into your right eye. So one of your eyes (maybe both), are receiving both the images into one eye, when it's only supposed to get one image. Just like your real eyes, each of our eyes sees its own point of view of the world and our brains combine the two and we see 3D, depth. If one of the eyes for some odd reason gets the same signal as the other eye, we would be seeing double and not a single 3D view. That would be weird huh.

Should you buy a professional grade silver screen or make your own? If you got the money, get a professional grade silver screen. Stewart Film Screens offer one of the best silver screens in the world, but they are also extremely expensive. There are a number of different companies out there that produce awesome silver screens and range in price. You can ask for a small sample from most of these companies and compare their screens and choose which one you think is the best or most bang for your buck.

However, If you're like me and don't have a lot of money to spend on expensive pro silver screens just yet and like the do-it-yourself motto. Then there's also an extremely inexpensive way of building your own silver screen and the results in the end are incredible considering the amount you'll have saved compared to buying one pre-made. In the end it only cost me $50 canadian to find a silver fabric to use as the 135" screen plus $20 canadian for the wood to be used as the frame. I've compared the silver fabric I found with most of the well known professional silver screens out there and it holds up against them especially when you compare the price and quality.

Now, in order to find the silver fabric I ended up using, I did have to go through a bit of work to find it. I went to a couple of local fabric stores, bought a ton of silver fabric samples I thought might work. A great way to test out how well the polarization properties hold up in the silver fabrics is by taking a pair of 3D polarized glasses and a flashlight. Shine the flashlight at the silver fabric, hold the 3d glasses in front of the fabric where the flashlight is shining and rotate the 3D glasses and see how well the 3D glasses block and lets light through. If your able to rotate the glasses so it goes completely black, you've found a pretty good silver fabric that has great polarization properties. But that's only half the battle, sure the polarization is great, but what about when you project an image on this silver fabric? How good does the image look? Well again, that depends on you and what you find acceptable. Before I found the perfect silver screen, I had spent maybe $30-40 on samples, not too bad.

One additional problem I faced with the 'perfect' silver screen I found was that it had a very ugly looking bright hot spot on the screen due to the reflective properties of the silver fabric. I could see the bright white light coming from the projector on my screen and it was just unacceptable. Luckily I was able to find a quick and easy solution to this. I went to my local home depot store and grabbed an aerosol spray can called Tremclad Clear with a Satin shine. I sprayed this over my entire screen and there goes my hotspot, now it was perfect and ready to be used.

[ignatius]

2 x Polarized Filters
There are two main types of polarized filters. Linear and circular. A quick google search on these two filter types will teach you everything you need to know about how they work with accordance to light. IMAX uses linear polarized filters. RealD uses circular. The difference? With linear polarizers, because of the way light travels through them, you can't tilt your head while you're watching the movie or else the 3D effect will be lost. You'll be sending the wrong information to both eyes so the illusion won't work anymore. Circular filters let you tilt your head around a lot more without having any negative effect on the 3D imagery. This may not be 100% true but, linear polarized filters produce less ghosting (cross-talk) than circular polarized filters. From my testing between the two I opted for linear polarized filters because of the minimal ghosting effect. Not only that, linear polarized filters and glasses are much cheaper than circular. And who really cares about not being able to tilt your head, I don't normally find myself watching a movie or playing a game with my head tilted 30-40 degrees.

There are a number of places you can buy these filters on the net, google is your friend. I have yet to buy a proper pair of linear polarized filters so at the moment I'm using a pair of cut up 3D glasses and put them on top of the lens of my projectors, as you can see in the pics.

Looks pretty professional right? Yeah, I know it sucks. But hey, the point is, using even simple 3d glasses as your filters for 3D still works really really well. Some brands and types are better than others that allow more light to get through the filters as well as less ghosting. But, the biggest factor that will determine how much ghosting you see will be with the silver screen. So, spend your money on a solid screen first than get a decent pair of filters.

This may or may not be obvious but just to be clear here. You can't use linear polarized filters on your projectors and wear a pair of circular polarized 3D glasses or vice versa. Just won't work. Your filters and 3d glasses have to match.

[ignatius]

Optional Equipment (if necessary):

A Mirror
If you have a small room, or a projector that has a long throw range like mine does and you're not getting the screen size you were hoping to get because you don't have enough room. Well to solve that issue, you can use a mirror to bounce the projected image coming from the projector to the screen like the setup I have here in the pics I posted up.

A few things to know about using mirrors to bounce the image around. Use 'front surface mirrors'. These mirrors will retain most of the light as it bounces off to the screen. You will also avoid seeing a double image. Most of the mirrors people use in their homes are 'rear surface mirrors'. Where the mirror is in the back covered by a thin layer of clear plastic so it gets protected by scratches and such. Because of the plastic layer, when light hits the mirror, it has to go through the plastic layer then reaches the rear mirror and bounces back again through the plastic to the screen. This will create a double image out of your single image. Some websites will show you some good diagrams of how that looks. Because front surface mirrors don't have that protective plastic layer. It's very fragile and easy to scratch. Not only that, front surface mirrors are usually quite expensive. But, once again if you search around on google, there are a number of tutorials people have posted on how to make your cheap rear surface mirror into a front surface mirror.

I was planning on using one of my rear surface mirrors and using one of the tutorials to turn it into a front mirror. But, when I tested out how well the rear surface mirror worked. I was surprised with the results. I barely noticed this 'double-image' effect that’s supposed to occur with rear surface mirrors. I had to stand 1-2 feet in front of the screen to see what I thought was the double-image effect. So, I decided the rear surface mirror was good enough for now instead of going through the hassle of making a front surface mirror. I probably lost a bit of light as well using the rear surface because of the plastic layer. But I was pretty happy with the results for now.

The optimum position and angle of the mirror should be placed at the center of the screen at a 45-degree angle. It is also better to angle the mirror vertically and not horizontally. If you angle it horizontally you will introduce focus problems where one side of the screen is clear and it gradually goes out of focus as it goes across the screen to the other end.

[ignatius]

Finished, 3D-time!

So, that's it, it's that easy. It may seem a bit daunting or complicated at first if your new to 3D, but it's very easy to understand it all over a short time. It's very basic stuff. If you check out the 3D I'm seeing, it's pretty awesome with the setup I have and it's not even complete yet. I still have to make a better stand for my projectors instead of the thing its sitting on right now shown in the picture. The way I placed the filters on my projectors isn't a good idea and I'm planning to build a proper filter holder when I get better filters. I'm still using some crappy 3d glasses that I'm using as my polarized filters. So if I purchased better filters I would get a much brighter image plus a lot less ghosting which I'm not getting much of anyway. I'm using a rear surface mirror, so I'm losing light there. If you have the money to buy a front surface mirror or to make one. You'll be able to achieve better lighting as well as low ghosting. And the silver screen itself is hand-made used by fabrics found by your local fabric store. Imagine how much better a professional grade silver screen would be. I just hope my setup proves that you can make a very cheap, dirty, and affordable 3D home theatre with pretty kickass results. And if you got the money to buy higher grade equipment, you'll get an even better experience and quality. Once I complete my setup properly, I will post up more pictures again.

Total cost for my 3D theatre using passive stereo setup:
2x Projectors = $2000 ($1000 per projector)

DIY Silver screen
Silver fabric = $50
Wood frame = $10
Black fabric for frame = $10
Searching for right fabric = $30

Polarized filters = $1 for a pair of 3d glasses

I hope this tutorial has been helpful and attracts some more people into 3D and helping them understand how it all works. If there's something I forgot to mention or something that wasn't made clear. Let me know and I'll get back to you as soon as I can.

Varinder C.
devilry.singh@gmail.com

[ignatius]

I'm working on a new stereoscopic 3D website, at the moment this is the temporary website to get the best deals 3D products from movies to tv's. click ---> 3d movies

[motorman45]

hate to be late to this thread but have you seen the omega 3d filter setup ?. its not polarizing and not Dolby, you dont need a silver screen. its been talked about on here in other threads and on avs forum.
you have a very cool setup, whats going to be on your website. ?
here is that alternative filter system

http://www.youtube.com/watch?v=RiWf_69xHW0