This is topic Silver Screen and Dual Projector 3D in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.
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Posted by Martin McCaffery (Member # 37) on 12-08-2011, 11:49 AM:
With Dual Projector 35mm 3D, is a silver screen necessary, or just recommended?
Posted by Gordon McLeod (Member # 33) on 12-08-2011, 11:57 AM:
Yes since the odds are you would use polarized filters on each projector
Posted by Steve Guttag (Member # 268) on 12-08-2011, 12:12 PM:
The Panavision system can be done with a white screen.
Posted by Mark J. Marshall (Member # 1409) on 12-08-2011, 12:34 PM:
What's the Panavision system?
Posted by Sam D. Chavez (Member # 1841) on 12-08-2011, 01:02 PM:
Similar in concept to Dolby 3D.
Posted by Mark J. Marshall (Member # 1409) on 12-08-2011, 06:40 PM:
Is that something new?
Posted by Louis Bornwasser (Member # 3063) on 12-08-2011, 07:54 PM:
Similar to Tech 3D in that it is single film. Glasses/filters similar to Dolby. Louis
Posted by Sam D. Chavez (Member # 1841) on 12-08-2011, 09:27 PM:
Panavision also works with D-Cinema as well, although I don't know if it has been implemented that way to date.
Posted by Mark J. Marshall (Member # 1409) on 12-09-2011, 06:05 AM:
Interesting.
I while back I asked if Dolby 3D filters and glasses would work for film and the answer was "no" because the filters are aligned with the red/green/blue light that comes out of the digital projectors and since film uses yellow/magenta/cyan they wouldn't work. It sounds like you're saying that the Panavision system glasses are aligned with the yellow/magenta/cyan of film. If that's true, how would they work for digital projectors' red/green/blue light?
Posted by Steve Guttag (Member # 268) on 12-09-2011, 06:31 AM:
I believe the Dolby system would work...BUT you would not have it color balanced and with no way to color balance it. As for Panavision, they do not create a dramatic color shift, it is done with comb filtering. It is entirely possible to do the Panavision system with 2-projector 3-D too.
Barco, now has a Panavision option for their projectors (Barco supplies the mechanism for their projectors on the Dolby/Panavision systems)...I presume Panavision has a rig, similar to Dolby's for other brands of projectors...except Sony, of course.
The Panavision and Technicolor 3D lenses are identical except for the filters so single lens 3D is also possible on film.
-Steve
Posted by Kevin Fairchild (Member # 4985) on 12-09-2011, 12:12 PM:
Ummm..... where would you even get content? And have fun making sure everything is spliced just right on both prints.
Posted by Steve Guttag (Member # 268) on 12-09-2011, 12:19 PM:
Content? Any of the Technicolor prints will run on the Panavision system. As for 2-projector prints...those too are available if you are on the right list...they would be of classic titles like Dial-M for Murder and such.
-Steve
Posted by Chris Slycord (Member # 4239) on 12-09-2011, 01:07 PM:
I think he might asking about digital content (based on how the discussion drifted and all) and I would assume that regular 3D dcp's would be used but I could be wrong.
Posted by Jack Theakston (Member # 4484) on 12-09-2011, 02:41 PM:
While we're on it, has anyone had experience with PAINTING your matte white screen silver? Are they all crap or are there people who can really do this properly?
Is it possible to adapt the Panavision or Dolby systems to 35mm projection?
Posted by Chris Slycord (Member # 4239) on 12-09-2011, 03:12 PM:
Panavision works with 35mm and digital.
Posted by Steve Guttag (Member # 268) on 12-09-2011, 06:16 PM:
As for dual projector 3D in the digital world...same files work for either single or dual projector...as it is, the player is sending out two different signals...so in a dual projector, one goes to each (unless you have a dual-dual player in which you can send 4:4:4 to each...the IMBs will allow 4:4:4 on 3D as well).
-Steve
Posted by Carsten Kurz (Member # 5396) on 12-09-2011, 06:59 PM:
Sony licensed Panavision for their Split-Lens as well, so they now have a choice for non-metallized screens as well.
@Jack: There is a thread in this forum dealing with silver screen paint and that some/most IMAX 3D screens have been painted on location because ist was impossible or too expensive to ship silver screens that large. But I think the results are suboptimal compared to todays high-performance silver screens from Stewart or Harkness. Everyone hates silverscreens, so one should probably get the best currently possible in order to reduce the known sideeffects.
- Carsten
Posted by Louis Bornwasser (Member # 3063) on 12-09-2011, 08:34 PM:
Jack: on digital PAINTING is not-an-option; precluded by contract. Louis
Posted by Jack Theakston (Member # 4484) on 12-09-2011, 10:01 PM:
Sorry, I should have been more specific—my theater is interested in running 35mm 3D (revival, not 1st run), but we've got a large screen (40x20) and we're weighing the financial difference between painting and getting a new silver screen all together.
In our case, we're not as worried about side seating fall-off, since the house is fairly narrow.
Posted by Steve Guttag (Member # 268) on 12-10-2011, 07:38 AM:
Imax has been the best at painting but they put up an automated paint rig to get an even coverage. I have NEVER and I mean NEVER seen a good hand painted silver screen...they are all uneven. Also, one has to block off everything behind the screen.
I would definitely recommend replacing the screen if you want good results.
-Steve
Posted by System Notices (Member # 2357) on 10-29-2014, 03:51 PM:
It has been 1054 days since the last post.
Posted by Alejandro Mir (Member # 7129) on 10-29-2014, 03:51 PM:
Hi all,
I recently installed a large dual 3D projection system with two Barco DP4K-32B and Dual IMB Showvault, using Schneider circular polarizers. The screen is an MDI Stereoview 2.8 gain, size 75`x40` and the throwing distance is 90`.
Everything seemed perfect until we played subtitled trailers... Hobbit and Exodus... there was a terrible ghost, very noticeable. I performed all the usual checks: confirmed each projector delivers the correct image, removed the porthole glasses to avoid any depolarization, checked another piece of silver screen surface, checked that the Master Image glasses match the polarization system, but the problem persists.
There's no doubt to me that the image from one eye is crosstalking to the other one. I measured a crosstalk rate of 22 with the Shcneider polarizers, also tested Master Image polarizers and the rate was 43. The ghost was sligtly lower, but still unusable.
I also tested linear polarizers and glasses, getting a rate of 75 and a barely acceptable ghost, but still not too good.
I've done few duals before and never seen this... I already tried everything posible without success...
Does anyone knows what the reason may be? Am I reaching the limit of the polarizing system? I doubt so...
Any suggestion? ![[Eek!]](eek.gif)
regards
Alex Mir
Argentina
Posted by Marcel Birgelen (Member # 6801) on 10-29-2014, 06:11 PM:
I doubt people really appreciate cross-posting while also reviving an old topic about 35mm 3D in the process.
Furthermore, I do think the Digital Cinema Forum is much more suited for this discussion.