Dolby introduces lighter, cheaper 3D glasses to better compe

Post by **Silversurfer** » Tue Mar 22, 2011 10:20 am

By Richard Lawler posted Mar 22nd 2011 6:46AM

Dolby has been working on getting the cost of its 3D glasses down since bringing Infitec color shift technology to theaters back in '07 and it couldn't wait for CinemaCon 2011 next week before announcing the new models seen above. These should please theater operators by being cheaper than the old ones -- down to $12 or less per reusable pair from $17 last year and $27.50 the year before that -- and hopefully cinemagoers by being lighter, with a new multilayer optical film from 3M and redesigned frame to help block extraneous light. There's also RFID tags to help keep them from walking out of the moviehouse, and it claims they will fit over 98 percent of prescription glasses. So far RealD has lead the market with its cheaper glasses, multiple styles and home HDTV cross-compatibility, while IMAX is synonymous (usually) with big screens, but if theaters start passing down that savings in the form of lower ticket prices we might pick out a Dolby screen among the other 3D theater competition the next time we head to the theater.

PRESS RELEASE
Dolby Announces Next-Generation 3D Glasses at CinemaCon 2011

High-performance, stylish, reusable 3D glasses deliver cost savings to exhibitors and improved comfort to moviegoers

SAN FRANCISCO--(BUSINESS WIRE)-- Dolby Laboratories, Inc. (NYSE: DLB) today announced the availability of its next-generation Dolby® 3D glasses. Designed with Dolby's 3D technical know-how, the expertise of a leading eyewear design company, and 3M's new multilayer optical film lenses, the glasses are compatible with Dolby 3D Digital Cinema systems currently installed.
Dolby's Next Generation 3D Glasses (Photo: Business Wire)

Dolby's Next Generation 3D Glasses (Photo: Business Wire)

"With the newly designed Dolby 3D glasses, we look to maintain the premium quality visual performance that Hollywood has come to expect from Dolby 3D, while providing a more comfortable fit for cinemagoers and a lower price point for exhibitors," said Matt Cuson, Senior Marketing Director, Cinema, Dolby Laboratories. "The next-generation Dolby 3D glasses strike the perfect balance between style and performance and are designed to be used repeatedly, bringing per-ticket costs well below disposable single-use 3D glasses."

The new glasses are currently available at a list price of $12.00 or lower when purchased with a Dolby 3D bundle. Dolby also plans to make children-sized glasses available next quarter.

New Technology Increases Performance

* Dolby has partnered with 3M to develop a new multilayer optical film lens that greatly reduces the weight of the glasses, increasing comfort while providing the excellent optical performance moviegoers expect from Dolby 3D.
* A more robust mechanical design, the new nylon frame features wide side temples and a shelf along the top edge of the frames, which help prevent extraneous light from entering the glasses, reducing internal lens reflections.

Style Enhances Comfort

* Updated industrial design makes both the audience member and the movie look marvelous.
* The new frames fit comfortably over 98 percent of prescription glasses and are well-suited to youth and adults.

More Robust for More Use

* The next-generation Dolby 3D glasses can withstand the rigors of many wash cycles and can be reused hundreds of times.
* The new 3M lenses are scratch resistant and include an antireflective coating.

RFID Tags Added for Tracking

* Beyond the antitheft tag included in previous generations of Dolby 3D glasses, the new Dolby 3D glasses also include individually serialized RFID tags.
* These tags can be used for inventory tracking and management.

New Lower Cost

* Dolby 3D glasses are high-performance, environmentally friendly, passive glasses that require no batteries or charging.
* Because they are reusable, the per-ticket cost of Dolby 3D glasses can be well below the cost of disposable 3D glasses.
* The new glasses are available at a list price of $12.00 or lower when purchased with a Dolby 3D bundle.

Exhibitors interested in learning more about Dolby 3D should contact their nearest Dolby reseller or Dolby sales office, or visit Dolby in booth (1600A) during CinemaCon 2011 at Caesars Palace.

About Dolby 3D Digital Cinema

Dolby 3D Digital Cinema technology, in conjunction with digital cinema projectors featuring Texas Instruments Digital Light Processing™ (DLP) technology, provides exhibitors with an efficient and flexible solution designed to deliver a superior 3D experience. Dolby's 3D solution uses a unique full-spectrum color-filter technology that provides realistic color reproduction and extremely sharp images. Since launching in November 2007, Dolby has shipped over 7,600 Dolby 3D systems and has one of the largest global footprints with over 400 exhibitor partners in 67 countries.

About Dolby Laboratories

Dolby Laboratories (NYSE: DLB) is the global leader in technologies that are essential elements in the best entertainment experiences. Founded in 1965 and best known for high-quality audio and surround sound, Dolby creates innovations that enrich entertainment at the movies, at home, or on the go. For more information about Dolby Laboratories or Dolby technologies, visit http://www.dolby.com" onclick="window.open(this.href);return false;.

Dolby and the double-D symbol are registered trademarks of Dolby Laboratories, Inc. DLP Cinema is a trademark of Texas Instruments. S11/24064 DLB-G

Show full PR textCrunchGear
Dolby

http://www.engadget.com/2011/03/22/dolb ... compete-w/" onclick="window.open(this.href);return false;

Post by **Fredz** » Tue Mar 22, 2011 10:42 am

Nice news, I hope we'll be able to find glasses and filters for personal use at much lower prices than what they are now. Could be a good boost for all the DIYers using dual projector solutions, maybe I should have waited a little bit before buying that 120Hz DLP projector...

Post by **BlackShark** » Tue Mar 22, 2011 1:29 pm

I learned something i didn't know :
The manufacturer of Dolby's infitec filters is 3M.

It's good to know if you need the material and dolby doesn't want to sell it to individual end users, you can try 3M directly.

Post by **Likay** » Tue Mar 22, 2011 1:51 pm

Recently got two pairs of dolbyglasses with glassbased lenses. They cost ~250SEK~27Euro @ pair and surely is a tad expensive. They are also available in plastic but they were not recommended, not even for testing purpose. Need to make a decent holder for the filters before i'm able to make some experiments.

Post by **cybereality** » Tue Mar 22, 2011 7:32 pm

Thats good they are keeping cost low. I wonder if there is any way to use this method for a home solution (ie a commercial product, not DIY).

Post by **europanorama** » Mon Apr 04, 2011 10:48 am

For the FIFA Soccer Championship-Final-3D-Cinema in switzerland we had to pay 2 chf/usd only for good-quality plastic glasses which could be worn over our own glasses. real D 3D signed.

BTW: why are we still waiting for the blueray3d?

Post by **cybereality** » Mon Apr 04, 2011 12:45 pm

europanorama wrote: BTW: why are we still waiting for the blueray3d?

Who's waiting for Blu-Ray 3D? It came out last year.

Post by **jackbauer** » Tue May 10, 2011 8:48 am

Likay wrote:Recently got two pairs of dolbyglasses with glassbased lenses. They cost ~250SEK~27Euro @ pair and surely is a tad expensive. They are also available in plastic but they were not recommended, not even for testing purpose. Need to make a decent holder for the filters before i'm able to make some experiments.

Hello Likay,
Can you elaborate about your "not recommended" comment? I intend to get plastic glasses for testing.
I understand they cannot be used as filters for the projectors as they are plastic and could melt. But what about using them as glasses? Would there be any difference at all with the regular ones?

Dolby is now listing cat834 (glass) and cat830/832 (plastic).
Regular cat834 use spherical glass lens but cat830/832 seems to use cylindrical plastic lens.

Does anybody know the differences between cat830 and cat832 other than frame design?? I can get any kind so I want to be sure.

cat830:
http://www.marlinwire.com/docs/Dolby3D_ ... ealers.pdf" onclick="window.open(this.href);return false;

cat832:
http://www.engadget.com/2011/03/22/dolb ... -compete-w" onclick="window.open(this.href);return false;

What about the so-called antireflective coating they are proud of?
It seems very reflective to me:
http://www.3doptix.be/en/Dolby-3D-glass ... x.tpl.html" onclick="window.open(this.href);return false; (enlarge photo)

Jack

Post by **Likay** » Tue May 10, 2011 3:46 pm

Ok. I guess it needs some elaborating: According to the guy i talked to, the plastic ones are a lot easier damaged and the filterproperties are also worse than the glasses ones. I took his word for it and if this would work decently i'd probably get glasses ones anyway so...

About ar-coating of the glasses: As a layman i guess that the ar-coating decreses reflections but only for the three narrow wavelengths of the specific filter (the filters seem to reflect every other wavelengths by design). Since these three wavelengths only covers a very tiny bit of the whole spectra the difference won't be noticed by just observing the reflection: The difference appear if you measure the actual light throughput. If i'm not wrong it's about 5% increase for the ar-coating of spar-filters. It should be about the same for sony/infitecfilters.

Some info what's happening even if somewhat wrong thread:
The aperture size of the filters is very small but enough for my beamers if i put them close to the lense. However, since the're very reflective (almost easiest described as mirrorsunglasses when looking from a tiny distance) i'm a tad anxious of using them for longer periods in case that the reflected light could harm the projectors.
So far i just made some small experiments but still needs to make a holder for the filters. Since i'm not sure if the projectors can handle the reflected light i'm practically a little stuck for the moment. Tilting the filters a little could work but ghosting increases massively. Turning them completely around works but maybe even then the projectorlense could focus the beam to something harmful.
I've tried gaming a little with them though and strangely my eyes adapt very well to the difference between the colors after just a little while. I do feel need of colorcorrection but practically i'd probably make a decent compromise between light and correct colors. I have yet to even try out your scripts since i have the learningcurve to defeat.

Attaching some initial images of colorreproduction but as said i need some info about how harmful longtime usage could be for the projectors before i proceed and eventually find out the hard way.

The projectors are hitachi cp-x260.

No filter:

Right eye filter:

Left eye filter:

On the hardware side i have a little idea of modifying the projectors themselves (3-lcd-projectors operate using dichroic mirrors) but i need to get suitable dichroic mirrors designed for the specific colors at 45°. I haven't in theory calculated what specific wavelengths the filters should be designed for yet (should be ~41% shorter when used at 45° unless the colors are specified for this angle...).
Lee-filters do have quite a number of dichroic filters but i haven't checked compability yet. The blue will almost be in the uv area ~300nm or so. Lee doesn't even specify wavelengths in this area so it's a little troublesome...
Besides the dichroic mirrors needs to be a little special: One mirror should reflect everything but the specific blue i want for infitec. Another filter should reflect only the green portion and letting through all colors with longer wavelengths (red) and finally a mirror for the red one. Since 6 dichroic mirrors are needed + properties needs to be different i'm not even sure it's possible to get a hold of such so chances are pretty high that nothing will happen. So far i prefer linear polarization before dolby/infitec but honestly i need to try it out more. The screen tried with infitec is still my old silverfabric for instance...

Post by **jackbauer** » Wed May 11, 2011 2:56 am

OK Likay, I agree with your comments on ar-coating. The best I can do is getting a pair of plastic glasses and do some testing. In any case, only the inside of the glasses may benefit from ar-coating (specially if you wear prescription glasses underneath...)

I have also been worried about backward reflection from the projector filters.
That's one of the reasons why I got flat filters (320$). If you use filters from glasses, they may focus too much to the inside of the projector. That's only good for experimentation. Still I have been using them around 50 hours with lamps at full power with no problem (I have sXRD panels, same as LCos).

If we believe Infitec, using the filters externally on the lens is a valid implementation and must not harm anything.
http://www.avsforum.com/avs-vb/attachme ... 1277480362" onclick="window.open(this.href);return false;

They recommend to set the filter exactly perpendicular to the light beam. I personally slightly tilt them a few degrees. Reflection is proportional to the angle but, as wavelenght shift is only proportional to cosine, there is no ghosting issue because of the tilt. I do not know if the tilt has any effect at all, but I want to be on the safe side... (IR dichroic filters for the lamp are always tilted)

Also, because the filters are flat, the backbeam is diverging and a very small portion of the 60% back light is actually reaching the panels. I am very confident about that (I was not when using curved filters form glasses). They are also larger and can be put farther from the lens.

...my eyes adapt very well to the difference between the colors after just a little while

If you are (almost) pleased with the results as is, why not trying to do color correction through the projector's settings (*) instead of using my script (which is only for video)? Even if it is not perfect, it will definitely be a huge improvement over not correcting at all:
http://www.avsforum.com/avs-vb/showthre ... st20269971" onclick="window.open(this.href);return false;
(see also my last post on using color space).
See also: http://www.avsforum.com/avs-vb/showthre ... st20285063" onclick="window.open(this.href);return false; promising...

Good luck to integrate the filters inside the projectors! Very interesting. Let us know about your experiments.

So far I prefer linear polarization before dolby/infitec but honestly i need to try it out more

The question is: Would you use a silver screen when watching 2D ? Expected answer: "No I prefer a normal white screen for 2D, silver screens suck" (many professionals make that comment...). Why should it be different for 3D viewing? Of course, that's everybody's choice.

You just experimented Dolby3D on your silver screen. Try a white screen if you can. That's a biiiig difference in PQ....
http://www.avsforum.com/avs-vb/showthre ... st20412265" onclick="window.open(this.href);return false;

(*) EDIT: You may want to use one of the patterns below to do adjustments:
http://jptheking.free.fr/3d/2x1080p-pattern.jpg
http://jptheking.free.fr/3d/2x720p-pattern.jpg
If you use the double-wide screen and two DVI outputs, half of the pattern is projected through one filter while the other half is projected through the other filter.

Jack

Post by **AntiCatalyst** » Tue May 17, 2011 1:19 am

Likay: many projectors have an altitude mode that ups the fan speeds a bit. It's really there to compensate for the thinner air at high altitudes, but it'll work for you too if you're worried about frying your pj's.

jackbauer: i actually got MUCH better 2d PQ with my silver screen compared to my previous 1.0 gain plain-white one.. The silver screen reflects much less light onto and from my white ceiling and floors. This (and the fact that there's now less light to reflect) results in a very much increased contrast ratio, in my case I'd guess about a factor of 5-10. This is fact through physics, not an opinion.

I'm not saying it'll still be better in a completely light-controlled AND reflection-controlled(dark walls, ceilings and floors), but most people don't have a dedicated HT room and as such have to compromise with the demands of their wives or girlfriends. They don't want a bat cave for a living room.

EDIT; I read your link, and i just want to add that not all silver screens are as grainy and directional as the s240.

My Peroni one does have some grain, but I've only ever noticed it in Windows, where there's big, stable white surfaces. With a moving picture, there's just no way you'd notice it.
The peroni is far from 2.4 gain though, so that might be why it's less grainy and "hotspotty".

Post by **Likay** » Tue May 17, 2011 1:30 am

There's no such setting on my beamers though, besides i'm not sure it will help.
I'm more afraid of the light radiation which might maybe is reflected into the beamer again. While tinkering with the filters in front of the projectors i have a VERY intense focalpoint, exactly like using a koncave mirror in the sun.

Post by **AntiCatalyst** » Tue May 17, 2011 1:45 am

yeah that doesn't sound good at all, sounds like it might burn the LCDs or something. :/
What if you put them at an angle, just enough to shine past the lens? does that hurt the separation?

EDIT: Maybe they're too small for that since they're from a pair of glasses..

Post by **Likay** » Tue May 17, 2011 3:21 am

Tilting the filters too much result in ghosting but on the other hand using the filters in reverse also works. I'm still a little worried to use these longterm since the projectorlense will focus the beam again. As you say the lenses are too small for use at a distance from the lense.

Post by **Fredz** » Tue May 17, 2011 9:12 am

AntiCatalyst wrote:i actually got MUCH better 2d PQ with my silver screen compared to my previous 1.0 gain plain-white one.. The silver screen reflects much less light onto and from my white ceiling and floors. This (and the fact that there's now less light to reflect) results in a very much increased contrast ratio, in my case I'd guess about a factor of 5-10. This is fact through physics, not an opinion.

Wouldn't a silver screen give less deep blacks since more light is reflected to the viewer, which should not be very good for the contrast ratio ?

I'm still evaluating different solutions for a DIY screen, my room is light-controlled but my walls are plain white, so a silver screen could be a good solution if the contrast ratio is really enhanced.

Are the viewing angles very limited with this solution also, what would you consider a good cone of vision to be ?

Post by **AntiCatalyst** » Tue May 17, 2011 9:38 am

Fredz wrote:
AntiCatalyst wrote:i actually got MUCH better 2d PQ with my silver screen compared to my previous 1.0 gain plain-white one.. The silver screen reflects much less light onto and from my white ceiling and floors. This (and the fact that there's now less light to reflect) results in a very much increased contrast ratio, in my case I'd guess about a factor of 5-10. This is fact through physics, not an opinion.
Wouldn't a silver screen give less deep blacks since more light is reflected to the viewer, which should not be very good for the contrast ratio ?

I'm still evaluating different solutions for a DIY screen, my room is light-controlled but my walls are plain white, so a silver screen could be a good solution if the contrast ratio is really enhanced.

Are the viewing angles very limited with this solution also, what would you consider a good cone of vision to be ?

No, that light is the type of light we WANT, focused light straight out of the projector. The light that we don't want is the diffused light that's back-reflected from the ceiling, walls and floor. A silver screen cuts this diffused light down in two ways; it reflects less light there to begin with, and the light that does back-reflect onto the screen(lets say from the ceiling) will mostly bounce like from a mirror and end up on the adjacent surface(ie the floor) instead of into your eyes.

A prerequisite of this is that you have your projector ceiling-mounted, since the screen reflects light like a mirror; angle of incidence is the same/opposite as the reflection angle.

There is a viewing cone of course. In my case the hotspot is right where i'm sitting so i'm happy

it's not like it's unwatchable from anywhere else though, it just gets a little darker the farther away you get from the hotspot.

Post by **tritosine5G** » Tue May 17, 2011 9:50 am

Silver and DLP shutterrig is supercool match,less luma and less hold time = less sparkies , and we all know , sometimes less is more, especially if it's sparkies !!!
(btw this nexnix material here is very sparky when I shoot 1200 lumen at it and completely good with 500 lm )
rear projection ~30-60" : anti glare coated , as dark as possible
silver front projection ~100" + : as grey/matt as possible

everyone should have it!

Post by **jackbauer** » Tue May 17, 2011 10:40 am

Duplicated. Sorry. See next.

Post by **jackbauer** » Tue May 17, 2011 10:58 am

@AntiCatalyst
Well, I was not aware of this terrible hotspot I got, until I took a picture of it... Did you take pictures and do you have any numbers? Feeling is one thing and real numbers another.

In fact, yes, I do have a dedicated and light controlled projection room. That may explain the different opinions we have here. Also, if you are the only person in your audience, comparisons cannot be done.

@Fredz
About viewing angles, see:
http://www.mtbs3d.com/phpbb/viewtopic.p ... 0&start=23" onclick="window.open(this.href);return false;

This is for this layout:

If we accept that the audience reasonable seating lies in the bottom of the rectangle, we get a 0.29 worst case gain (51°) !!
EDIT: Complies with data from http://www.harkness-screens.com/digital ... al240.html" onclick="window.open(this.href);return false;
(seems that extinction ratio is about 20 for this angle. That's a lot of ghosting !!. To be compared with about 200-any angle with the Dolby3D tech)

Jack

Post by **tritosine5G** » Tue May 17, 2011 11:07 am

look , heres a topic about that,
http://archive.avsforum.com/avs-vb/show ... did=104630" onclick="window.open(this.href);return false;
I saw it when it still had the pictures, it was very convincing. Basically, you need both vertical and horizontal curvature to deal with hotspot, then you actually enlarge the hotspot itself and the gain will be super high without coating: 15+ gain spherical screen with pure aluminium... Then also tolerances come into play , IMO not nice.

For me, I find it usable with 500lm plus flat , silver texture is not evident, hotspot not evident, ambient rejection is there. Only thing I'd want is much less polarization loss / better dynamic behavior , then It would be 3-4x brighter! (MEMS glasses....)

ps.: LCD screens are brighter at the edges (because of edge lit) so some game developers even compensate for that , creating artificial hotspots .........blargh....

Post by **jackbauer** » Tue May 17, 2011 11:53 am

tritosine2k wrote:look , heres a topic about that,
http://archive.avsforum.com/avs-vb/show ... did=104630" onclick="window.open(this.href);return false;
I saw it when it still had the pictures, it was very convincing.

Yes, too bad the pictures aren't there any more..
Jack

Post by **AntiCatalyst** » Wed May 18, 2011 12:19 pm

jackbauer wrote:@AntiCatalyst
Well, I was not aware of this terrible hotspot I got, until I took a picture of it... Did you take pictures and do you have any numbers? Feeling is one thing and real numbers another.

In fact, yes, I do have a dedicated and light controlled projection room. That may explain the different opinions we have here. Also, if you are the only person in your audience, comparisons cannot be done.

@Fredz
About viewing angles, see:
http://www.mtbs3d.com/phpbb/viewtopic.p ... 0&start=23" onclick="window.open(this.href);return false;

This is for this layout:

If we accept that the audience reasonable seating lies in the bottom of the rectangle, we get a 0.29 worst case gain (51°) !!
EDIT: Complies with data from http://www.harkness-screens.com/digital ... al240.html" onclick="window.open(this.href);return false;
(seems that extinction ratio is about 20 for this angle. That's a lot of ghosting !!. To be compared with about 200-any angle with the Dolby3D tech)

Jack

That's almost like my setup, 2m wide screen at 3,3m distance.
Clearly we're talking about two very different screens here. I'm not the only viewer, and in fact i often sit in the far end of the couch(best spot lol) which is almost 1m further to the right of your "worst-case viewer". As i said though, my screen is far from 2.4 gain.

Post by **Fredz** » Wed May 18, 2011 4:56 pm

AntiCatalyst wrote:No, that light is the type of light we WANT, focused light straight out of the projector. The light that we don't want is the diffused light that's back-reflected from the ceiling, walls and floor.

Yes I got this, what I was saying is that the black levels which are not completely black due to projectors technology will be more reflected with a silver screen, hence making them even less black, which is also quite bad for the contrast ratio. I was wondering what was the main factor for the less deep blacks, the interreflections from the walls to the screen or the greyer blacks due to the silver screen.

AntiCatalyst wrote:There is a viewing cone of course. In my case the hotspot is right where i'm sitting so i'm happy it's not like it's unwatchable from anywhere else though, it just gets a little darker the farther away you get from the hotspot.

I forgot about the hotspot, this could be pretty bad for people not in a narrow cone of vision as is the case in my room since I guess they should see it shifted to one side or another of the screen.

Post by **Fredz** » Wed May 18, 2011 4:59 pm

jackbauer wrote:If we accept that the audience reasonable seating lies in the bottom of the rectangle, we get a 0.29 worst case gain (51°) !!

Ouch, that makes it incompatible with my room then. I'll probably evaluate curved screens then instead since I'm also building a DIY anamorphic lens.

Post by **jackbauer** » Thu May 19, 2011 4:30 am

As a layman, I will try to share my understanding on screens.

To make it short, there are three major classes of screens:
1. "normal" white screens. Reflection is uniform all accross the screen (should be)
2. silver screens. Direction of reflection peak is mirror-like
3. beaded screens such as Dalite Hipower (*). Reflects towards the source (beamer)

Reflections can be comprehended by the so-called lobe diagrams. Lets assume at the screen edge:

In all cases, the lobe area size must be the same (energy conservation).
In other words, if you gain light on the reflection peak angle, you definitely lose light on the other angles. Screens cannot amplify light, they simply spread it differently according to angles.

Screen type selection depends of you usage. A gamer who is the only person in the audience may select a beaded screen, as reflection is all directed to him. A silverscreen may also be used on the condition it is a curved screen.
If the audience is spread apart, a normal white screen is the obvious choice.
Unfortunately, polarizers require silver screens. If it is flat, it is the worst ever choice. But you simply cannot help it.
....unless you use Dolby/Infitec filters of course....

(*) http://www.projectorcentral.com/da-lite ... review.htm" onclick="window.open(this.href);return false;

Jack

Post by **AntiCatalyst** » Thu May 19, 2011 7:11 am

Fredz wrote:Yes I got this, what I was saying is that the black levels which are not completely black due to projectors technology will be more reflected with a silver screen, hence making them even less black, which is also quite bad for the contrast ratio. I was wondering what was the main factor for the less deep blacks, the interreflections from the walls to the screen or the greyer blacks due to the silver screen.

That is completely irrelevant, since the brights are enhanced exactly as much as the blacks, so all you get is a brighter picture on the whole. A silver screen can't hurt the contrast ratio in any way, even in a pitch black, completely reflection-free room.

jackbauer:
You're contradicting yourself here. A silver screen isn't automatically worse than a beaded one.
As your own diagrams show, a retro-reflective screen has the exact same(but vertically opposite) viewing cone as a silver screen of the same gain.. so beaded vs silver is mostly a matter of where your projector is located in relation to the viewers. You want to reflect the most light to where the viewers are.

Did you take pictures and do you have any numbers? Feeling is one thing and real numbers another.

The feeling is what really matters, though.

don't obsess about numbers.
there is hotspotting. The image is darker on the sides. The only time you'll ever notice is when surfing the web or flipping folders full-screen in Windows. If that's what you use your projector for, get a white screen(or better, a computer screen) instead.

Not one of my friends have complained or even mentioned that it's darker on the sides or that the image looks brighter in one part of the screen. Not one. They have however, mentioned the fact that the image simply looks "better" and "more contrasty" when compared to my white screen.

Fredz; You can't make everything perfect for everyone in the audience. The way i see it, a white screen gives everyone in the audience the same, washed-out contrastless image. A reflective screen gives YOU the best image, and extreme side viewers a darker one(how dark depends solely on the gain value). And, unless all your friends are cineasts, noone will even see the difference.

Post by **jackbauer** » Thu May 19, 2011 11:07 am

AntiCatalyst wrote:jackbauer:
You're contradicting yourself here. A silver screen isn't automatically worse than a beaded one.
As your own diagrams show, a retro-reflective screen has the exact same(but vertically opposite) viewing cone as a silver screen of the same gain.. so beaded vs silver is mostly a matter of where your projector is located in relation to the viewers. You want to reflect the most light to where the viewers are.

AntiCatalyst, do you mind if I disagree? I think there is a misunderstanding somewhere.
If we try to compare highly reflective screens, we must do that with the viewer seated in the ideal location, which is, in both cases, as close as possible to the projector.

If we consider flat screens:
- Beaded screen: Every part of the screen is directly reflected back at you: There is absolutely no hotspot.
- Silver screen: Only the center is reflected back at you. The other areas are reflected at the walls and the ceiling (you increase ambiant light which actually lowers the overall contrast if your walls are white...). That is the definition of hotspotting. To achieve the same result, a silver screen must be curved (spherical).

Beaded screens also beats silverscreens for shifted viewers as there is still no hotspot but only a loss of overall brightness.

So I go on with my saying that a silver screen is automatically worse than a beaded one.... at least for flat screens. Sorry.
Of course you can disagree, that's your right.

Jack

Post by **AntiCatalyst** » Thu May 19, 2011 3:24 pm

jackbauer wrote:If we try to compare highly reflective screens, we must do that with the viewer seated in the ideal location, which is, in both cases, as close as possible to the projector.

that's not entirely true. with a silver screen, you want the projector in the ceiling(if you're seated below the screen center), while with a retro-reflective screen, the optimal projection position is basically with the projector mounted on your head(well, between your eyes really)

I realized that a retro-reflective screen for obvious reasons is entirely free from hotspotting just after typing my previous post, so i do agree that a beaded screen will have better PQ. But if you , like me, can't have a retro screen(ie have a ceiling-mounted projector) i'd much rather have a silver screen than a white one. Unless of course the room is a pitch-black bat cave.

Post by **Fredz** » Thu May 19, 2011 4:57 pm

AntiCatalyst wrote:That is completely irrelevant, since the brights are enhanced exactly as much as the blacks, so all you get is a brighter picture on the whole. A silver screen can't hurt the contrast ratio in any way, even in a pitch black, completely reflection-free room.

You are right, the contrast shouldn't change, but the blacks will still be a lot greyer. This shouldn't be much of a problem with dual-polarized 3D projection, probably much better even, but I don't use this kind of setup.

AntiCatalyst wrote:Not one of my friends have complained or even mentioned that it's darker on the sides or that the image looks brighter in one part of the screen. Not one. They have however, mentioned the fact that the image simply looks "better" and "more contrasty" when compared to my white screen.

You said (with reason) that the contrast shouldn't change with a silver screen, but your friends find the image "more contrasty". I guess it was while watching polarized 3D, otherwise it wouldn't make sense.

AntiCatalyst wrote:Fredz; You can't make everything perfect for everyone in the audience. The way i see it, a white screen gives everyone in the audience the same, washed-out contrastless image. A reflective screen gives YOU the best image, and extreme side viewers a darker one(how dark depends solely on the gain value). And, unless all your friends are cineasts, noone will even see the difference.

I still prefer everyone to see the same image, in my room people can be very excentred so a silver screen is definitely not an option. I guess a curved screen would be the best option in my case, or I could try to add black velvet behind the screen and on the proximate walls for something even better.

Post by **AntiCatalyst** » Fri May 20, 2011 12:53 am

Fredz wrote:You are right, the contrast shouldn't change, but the blacks will still be a lot greyer. This shouldn't be much of a problem with dual-polarized 3D projection, probably much better even, but I don't use this kind of setup.

what? increasing overall brightness is just like turning up your projector lamp to maximum. That doesn't hurt the contrast ratio, but a silver screen will? why?

Fredz wrote:You said (with reason) that the contrast shouldn't change with a silver screen, but your friends find the image "more contrasty". I guess it was while watching polarized 3D, otherwise it wouldn't make sense.

You misread me there. I wrote "can never hurt" implying that it could only help

Fredz wrote:I still prefer everyone to see the same image, in my room people can be very excentred so a silver screen is definitely not an option. I guess a curved screen would be the best option in my case, or I could try to add black velvet behind the screen and on the proximate walls for something even better.

Yes, black velvet is a great idea if you have a dedicated HT room!

I used to have a black bedsheet in the ceiling when i had my plain white screen.. But a word of advice: if you control the side/ceiling/floor reflections, what's behind the screen won't matter one bit! because very little light will be reflected there, and since it's behind the screen, it won't reflect directly onto the screen. I have a white wall behind my screen, and ever since i controlled my reflections, it's now very much darker and does not bother me at all.

Post by **jackbauer** » Fri May 20, 2011 2:58 am

AntiCatalyst wrote:
jackbauer wrote:If we try to compare highly reflective screens, we must do that with the viewer seated in the ideal location, which is, in both cases, as close as possible to the projector.
that's not entirely true. with a silver screen, you want the projector in the ceiling(if you're seated below the screen center), while with a retro-reflective screen, the optimal projection position is basically with the projector mounted on your head(well, between your eyes really)

I realized that a retro-reflective screen for obvious reasons is entirely free from hotspotting just after typing my previous post, so i do agree that a beaded screen will have better PQ. But if you, like me, can't have a retro screen(ie have a ceiling-mounted projector) i'd much rather have a silver screen than a white one. Unless of course the room is a pitch-black bat cave.

Your are right about the projectors mounted on the ceiling and the viewer'eyes beeing lower. Silverscreens can be tilted to focus on the viewer (must still be curved in any case). Beaded screens cannot. More than that, if you are using a stacked dual setup and a beaded screen, one projector is looking brighter than the other because of different angles. But this can be dealt with.

If the projector(s) are on the ceiling, there is no real advantage of using a beaded screen because the angle may give you much less than the 2.8 maximum gain (say 1.0 ?)

I think a good tradeoff could be a white screen with a gain of 1.4 for example. There are many of them available. No hotspot, good PQ, wide audience, NO need for a costly and complicated silverscreen. A curved screen distorts the picture when tilted.

Unless you are very fond of the polarized approach and absolutely dont want to part with it for any good reason, Dolby/Infitec is the best compromise at about the same cost. There is still the color correction issue but you can do it decently with the projector's settings and hopefully perfectly by the end of the year: http://www.avsforum.com/avs-vb/showthre ... st20285063" onclick="window.open(this.href);return false;

Jack

Post by **AntiCatalyst** » Fri May 20, 2011 9:16 am

jackbauer wrote:a white screen with a gain of 1.4 for example. There are many of them available. No hotspot, good PQ, wide audience, NO need for a costly and complicated silverscreen.

You're really starting to sound a bit brainwashed here. It's not the silver that's causing the hotspot, it's the reflectivity. White or silver, ANY >1.0 gain screen that isn't retro-reflective WILL have a hotspot. The severity of which depends on the gain value.

I can't seem to follow your infitec reasoning. You obsess about a hotspot that really is invisible whenever a movie is playing(you even said you werent aware of it), but "decently" correct colors between your two eyes is fine. well, have fun calibrating

Post by **jackbauer** » Fri May 20, 2011 9:29 am

AntiCatalyst wrote:
jackbauer wrote:a white screen with a gain of 1.4 for example. There are many of them available. No hotspot, good PQ, wide audience, NO need for a costly and complicated silverscreen.
You're really starting to sound a bit brainwashed here. It's not the silver that's causing the hotspot, it's the reflectivity. White or silver, ANY >1.0 gain screen that isn't retro-reflective WILL have a hotspot. The severity of which depends on the gain value.

Ok I already know that. "No hotspot": Of course there is hotspot on a >1 gain screen, technically. But with a gain of 1.4 its barely noticeable. In any case much less than with a 2.4-plus gain screen. That seems a good tradeoff for brightness vs angle of vision.

AntiCatalyst wrote:I can't seem to follow your infitec reasoning. You obsess about a hotspot that really is invisible whenever a movie is playing(you even said you werent aware of it), but "decently" correct colors between your two eyes is fine. well, have fun calibrating

With my two 1000 lumen projectors, I have plenty of light on a 2 meter wide white screen, after filter attenuation and color calibration.
Calibration step is over. Thanks. I am now enjoying my movies with magic 3D.

Jack

Post by **Fredz** » Fri May 20, 2011 11:23 am

AntiCatalyst wrote:what? increasing overall brightness is just like turning up your projector lamp to maximum. That doesn't hurt the contrast ratio, but a silver screen will? why?

You don't read what I write, do you ? I said that you were right about the contrast, but that the blacks would be greyer. My original question was only to know how much it was disturbing, but I guess you simply don't care.

AntiCatalyst wrote:You misread me there. I wrote "can never hurt" implying that it could only help

That would be possible if the screen gain was not uniform depending on the intensity of the hitting light, but I doubt that's the case. And even if it was, it should still be evaluated in which conditions the gain is the more important, with brighter lights or with dimmer ones. In the first case the contrast ratio would be better, but in the second one it would be worse.

AntiCatalyst wrote:But a word of advice: if you control the side/ceiling/floor reflections, what's behind the screen won't matter one bit! because very little light will be reflected there, and since it's behind the screen, it won't reflect directly onto the screen. I have a white wall behind my screen, and ever since i controlled my reflections, it's now very much darker and does not bother me at all.

I guess it would still be better to have a black wall behind, or at least only black borders around the frame. Most home-cinema amateurs do this to have a better perceived contrast ratio, that's also what is done on the vast majority of TV sets currently available.

Post by **AntiCatalyst** » Fri May 20, 2011 5:19 pm

Fredz wrote: I said that you were right about the contrast, but that the blacks would be greyer. My original question was only to know how much it was disturbing, but I guess you simply don't care.

Well then not at all, you can't see it because the rest of the image gets brighter as well(that's what i've been trying to tell you). In my case, i got very much deeper blacks(by less back-reflected light) while brightening the rest of the image. win-win!

Fredz wrote: That would be possible if the screen gain was not uniform depending on the intensity of the hitting light, but I doubt that's the case. And even if it was, it should still be evaluated in which conditions the gain is the more important, with brighter lights or with dimmer ones. In the first case the contrast ratio would be better, but in the second one it would be worse.

Contrast ratio is never worse with a silver screen than a white one, unless you have a very strange room(ie every surface being pitch black except the back wall). Lights on or off, it only helps the contrast ratio. There's a perfectly logical explanation for this that i could try to explain in a diagram if you can't understand it from my previous posts.

Gain screens are about so much more than just brightness!

jackbauer; sorry mate, just seemed strange that you'd write "no hotspot" for a reflective screen.

Post by **Likay** » Fri May 20, 2011 8:25 pm

I noticed that i have hotspotting when taking pictures of the screen. Until then i didn't see it at all. It's not a big issue but it is an effect i'd like to decrease.

Post by **jackbauer** » Sat May 21, 2011 2:07 am

Likay wrote:I noticed that i have hotspotting when taking pictures of the screen. Until then i didn't see it at all. It's not a big issue but it is an effect i'd like to decrease.

Likay, you shouldn't have done that. You will see it everytime now...

Jack

Post by **AntiCatalyst** » Sat May 21, 2011 2:36 am

likay, a camera has a very much lower dynamic range(essentially the same as contrast ratio) than a human eye, so the result is exaggerated a lot if you try to capture it with one.

Just tell yourself that it's all in your mind! well it is, mostly

Post by **Likay** » Sat May 21, 2011 4:15 am

jackbauer wrote:
Likay wrote:I noticed that i have hotspotting when taking pictures of the screen. Until then i didn't see it at all. It's not a big issue but it is an effect i'd like to decrease.
Likay, you shouldn't have done that. You will see it everytime now...
Jack

So very true.

AntiCatalyst wrote:likay, a camera has a very much lower dynamic range(essentially the same as contrast ratio) than a human eye, so the result is exaggerated a lot if you try to capture it with one.

Just tell yourself that it's all in your mind! well it is, mostly

Agrees. The centre of the screen have most of our attention which makes it even less noticeable. The difference between photos and what's experienced is huge. It's annoying knowing though.

Post by **jackbauer** » Sun May 22, 2011 4:08 am

Likay wrote: ... It's annoying knowing though.

Count +1 for Dolby...

Professional advices:
http://www.film-tech.com/ubb/f16/t000436.html" onclick="window.open(this.href);return false;

Mark Gulbrandsen :

[Dolby] 3-D effect is the same everywhere in the room and this is not the case with a system that relies on a Silver screen. You may loose 3-D completely in the front few rows and at the sides with silver screens.

Brad Miller:

...Dolby is the way to go. Silver screens suck,...

Julio Roberto :

If you don't like silver screens, you can fit dual projectors with passive Infitec filters ...

Not my word. I am unbiased...

Jack