Film-Tech Forum ARCHIVE: M.D.I. 3D silver screen

This is topic M.D.I. 3D silver screen in forum Digital Cinema Forum at Film-Tech Forum ARCHIVE.

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Posted by David Stone (Member # 4846) on 09-29-2009, 07:39 PM:

Has anyone installed or used a M.D.I. 2.2gain silver screen from canada for 3D, in particular for RealD, and does it comply with RealD'S requirements.

Kind Regards,

David Stone.

Posted by David Zylstra (Member # 4230) on 09-29-2009, 08:29 PM:

Last I knew the only screens RealD "approved" of were the MDI or Harkness (they also asked that we specifically said the screens were intended for RealD on the order to ensure we got the right coating). All of our RealD screens are Harkness.

I heard that Hurley has come up with a washable silver screen, but posts here mention issues with the surface; not to mention I don't think the Hurley is "approved" yet.

Posted by Mark Gulbrandsen (Member # 72) on 10-01-2009, 01:06 PM:

Very very definitely stay away from the Hurley washable surface! What a splotchy piece of crap! I do however reccomending checking out the Big Sky washable surface which is brand brand new. I was talking to the gal from Big Sky who was at the Mountain West NATO convention and she said it had been tested and approved by Real-D and it acuaually surpassed their specs. As with any NEW product such as the Hurley and Big Sky be very leery until it's prooven itself. My beef with Hurley is they would not stand behind a very obviously defective product. When I was at CLACO we installed an 84 by 56 foot MDI silver at Zion Canyon and it was a very nice surface...

Mark

Posted by Frank Angel (Member # 248) on 10-03-2009, 09:41 AM:

I had a few discussions about a year & a half or so ago with a tech from MDI who claimed that their 3D silver is lenticular and that's unique for the industry so far; lenticular silvers were abandoned around the time of the miltiplex construction. MDI's lenticular silver which makes a big difference (so he claimed) in eliminating or at least greatly reducing hotspots. What he said their goal was, was to make a truly dual purpose silver that can be used for 3D as well for 2D without the downside of the smooth surface silvers.

I would be interested in knowing if this is true or just hype. I know that Fox's original CinemaScope specification called for a curved silver lenticular screen (they called it the Miracle Mirror or something like that) because they wanted to compensate for the light loss. That lenticular surface and the curve mitigated the hot spot problem.

Last night my nephews dragged me to see FINAL DESTINATION and boy, the hot spot was pronounced -- we were sitting only slightly to the left side of the theatre and the whole right side of the screen was dark. I can't imagine how annoying this must be when this theatre shows standard 2D titles.

Posted by Mark Gulbrandsen (Member # 72) on 10-03-2009, 10:37 AM:

Well, Thast a load of crap! The one we hung wasa painted surface, was not lenticular and it also hotspotted just like any silver surface would. You can't paint on a lenticuluar surface!! UNless there is something very recenbt no one has made a true lenticular since Technikote stopped making their lenticuluar surface.

Mark

Posted by Brad Miller (Member # 2) on 10-03-2009, 12:03 PM:

Frank, if you go see Final Desination in a Dolby 3D auditorium, I think you will find noticeably different (and better) results. [Wink]

Posted by Mark Gulbrandsen (Member # 72) on 10-03-2009, 12:49 PM:

quote: Brad Miller
I think you will find noticeably different (and better) results.

Dolby can also hot spot just as well if any of the new high gain white surfaces are used. Harkness does make a 2.0 gain white sheet!! Actually, I have seen far more variance in brightness amongst the locally installed Dolby systems than in any of the other polarized systems. The Dolbys can range from decent rightness to not even watchable. You just do not know what you're going to be seeing... even in the same location!! I'm debating on weather to even go see the Toy Stories in 3-D or not and weather my eyes could take that low of light level for that amount of time.

Mark

Posted by Brad Miller (Member # 2) on 10-03-2009, 03:00 PM:

If the screens are that dark, then the person who decided the specs in that auditorium shouldn't have that job. There is no excuse other than just being CHEAP and not giving a shit about the customers.

Posted by Demetris Thoupis (Member # 833) on 10-03-2009, 03:17 PM:

1.4 gain for Dolby is the best compromise solution for wide auditorium. 1.8 starts the Hot Spot syndrome and I don't even want to think of 2.0
Demetris

Posted by Frank Angel (Member # 248) on 10-04-2009, 01:30 AM:

quote: Mark Gulbrandsen
Well, Thast a load of crap! The one we hung wasa painted surface, was not lenticular and it also hotspotted just like any silver surface would. You can't paint on a lenticuluar surface!! UNless there is something very recenbt no one has made a true lenticular since Technikote stopped making their lenticuluar surface.

OK, so if that's the case, AND if it is true that lenticular will still hold polarization (no idea if that is true or not since this sales guy was handing me a load of bs from top to bottom), then it would behove Technikote or other manufactures to jump in an start making lenticular sheets again given that it looks like 3D is going to be with us for at least a decent short term, maybe longer. It really would be nice to have a dual purpose screen that one didn't have hide in shame when running 2D on it.

Posted by Mark Gulbrandsen (Member # 72) on 10-04-2009, 11:42 AM:

quote: Brad Miller
If the screens are that dark, then the person who decided the specs in that auditorium shouldn't have that job. There is no excuse other than just being CHEAP and not giving a shit about the customers.

Brad... I couldn't agree more. Don't forget you are the loaner out there that is doing it right!! Few others do it right even fewer care in the least.

Frank... Technikote was bought up by Big Sky. They won't be producing any lenticuluar sheets. They are however producing a silver sheet that is not only washable but it is a nice consistant surface.... not splotchy like Hurley's sheet is.

Mark

Posted by Frank Angel (Member # 248) on 10-04-2009, 11:56 AM:

Ok, so then the questions still remain, 1) will lenticular hold polarization and if yes, then 2)how come no one is making what seems like it would be a perfect solution for a screen that will work well with 2D as 3D with the elimination or reduction of hot spots?

Posted by Steve Guttag (Member # 268) on 10-04-2009, 01:35 PM:

Lenticular screens do NOT prevent hot spots...they limit cross-reflection (aka self illumination). They were more popular for curved screens, not Silver ones.

I don't see why a lenticular surface would prevent the keeping of polarization, however, the hotspot will remain...just the contrast would improve on a curved silver screen IF the image was self-illuminating the edges from cross-reflection.

Steve

Posted by Frank Angel (Member # 248) on 10-04-2009, 03:11 PM:

Thanks Steve -- so silver, be it smooth or lenticular, will equal hot spots, just that lenticular will reduce cross reflection plus better light to the audience as one normally gets with any properly curved screen.

So much for the claims of the MDI sales guy. He would have done well in the used car business.

Posted by Gordon McLeod (Member # 33) on 10-04-2009, 04:37 PM:

MDI 3d screens are textured not sure if one would say lenticular

Posted by Andrew Lee (Member # 1330) on 10-05-2009, 11:17 AM:

Well it would take a 3D screen topic to bring me back to this board. I find it necessary to comment on some of the posts.

In no particular order:

- The MDI screen at Zion is a great screen and is not a lenticular surface. Mark, you did an awesome job of installing that stuff in record time.

- However,most MDI silver and a few 1.4 and 1.8 do have a lenticular pattern embossed onto the vinyl prior to painting. It is not the old style lenticular vertical pattern that some of you remember. It is a very small diamond pattern. Lenticular can refer to any pattern, embossing, or texturing on a screen surface that acts in a way to intentionally direct light differently than a flat surface.

- The combination of this pattern and the right paint distributes the light to a point that can diminish the hotspotting effect by spreading out and lessening the intensity of the light. Easier said than done but in essence MDI does have a lenticular screen (no BS Frank or used car salesmen).

- This is one of the rare times I would disagree with Steve. A proper custom lenticular design combined with the right coating can theoretically and has in one case completely eliminated the hotspot. Too expensive to make in the real world.

- Screen manufacturers have been trying to make silver and high gain lenticular screens for over 80 years. Making one that meets todays expectations of looking as good as a matt white screen is simply close to impossible. The end product would be too expensive if you could solve this issue.

- As long as the coating is of a metallic base it will maintain polarization on a lenticular surface as Steve mentioned.

- Mark, why can't you paint a lenticular surface? Then again if you are refering to the multi-layered ribbed screen surface I just thought of, you would be correct. When I am referring to lenticular, I am not referring to the ones that have optical films.

- Frank, just to reiterate, yes a silver lenticular screen with the right pattern, depth and coating is the holy grail, it simply can't be done to it's potential without costing at least 10x what a silver screen costs today. If it was that easy, everyone would be making one.

Andrew

Posted by Alan Gouger (Member # 543) on 10-05-2009, 11:29 AM:

I have found with any Silver or high gain screen visible pixel interaction from fixed pixel displays ( all digital projectors ) that looks like shimmer or sparklies that is not there with film.

By the way does anyone have a link to MDI screens. I could not find anything. Thank you.

Posted by Steve Guttag (Member # 268) on 10-05-2009, 08:54 PM:

Andrew

quote:
- This is one of the rare times I would disagree with Steve. A proper custom lenticular design combined with the right coating can theoretically and has in one case completely eliminated the hotspot. Too expensive to make in the real world.

I'll be happy to concede this, once I see your data. That is, I would want to see the same projector/lens with the equivalent of a PSA200 type chart to show how the hot spot has been "eliminated". A Torus screen can almost eliminate a hot-spot too...without lenticules but the bring other undesirable artifacts. A lenticule is going to control the light like a blinder on a horse...this will help prevent scatter but I don't see how it helps with the prevention of hot-spotting...which is cause by the very narrow scatter of the Silver screen. Cinerama used lenticulated screen material (by Hurley Screen Corp) to aid in stopping self illumination. However, rather than diamond shaped, they were box. They did a reasonably good job too as well as the louvered manner in which it was constructed.

I would presume you went with a diamond pattern rather than grid to avoid Morie patterns from digital pixels aligning on the same grid.

I would think there would also be measurable contribution of the lenticules to the sound as they would act like minature horns right in front of the perforations.

Interesting stuff, for sure...but I would want to see the data before passing judgment on how well it accomplished its goal and what possible unintended affects came out of it.

Steve

Posted by Mark Gulbrandsen (Member # 72) on 10-05-2009, 09:30 PM:

Andrew,
I stand corrected and thank you for chiming in on this. I agree that I'd like to also see some data however anyone attempting taking a step like this is a step foreword in my opinion. One thing that bothers me a bit is the fact that you emboss first and then paint over the emboss. I just don't see alot of consistancy happenning there even with automatic spraying machines. Have you considered creating a coated surface first and then emboss as in the old days? That would also bring you back to being able to do the ideal shaped lenticles. Once a screen is painted the paint is going to run a bit even if it's microscopic amounts and so on then the lenticles you have ambossed are not what you intended them to be. Even a textured paint or varying texture across the width with something in it that helps even out the hot spot? I seem to remember reading that the original D-150 screens had varying size lenticles as you went across the screen to control reflection vs angle. IMHO in this technological age something like this should still be easily possible. D-150 did this on a small scale and screen companies are making silver screens like never before... IMHO, the technology just needs to go in reverse to catch back up with today!

Mark