Adding 3D

[Armand Daiguillon]

I've never worked at a theater that did any kind of 3D, but i've had some requests lately and am thinking about upgrade possibilities.
We have NEC 900C projectors, I know they are capable, but what hardware exactly needs to be added to get 3d ? (a polarizer or something ?)
And to be blunt, hows would the quality be with these projectors ? Light output doesn't seem very high on these projectors and 3d always looks dim to me ....

Anybody ever upgraded theses ?
Any feedback on the cost and quality ?


Thanks !

[Ioannis Syrogiannis]

The more efficient of the 3D systems are the dual projector ones. The single projector will achieve less than 30% of the light. (I think, but not sure, that the top claim is about 26%?)
That will tell you about quality. If you want to have the 4fl that is the goal, you will probably need to change the screen gain by using a silver screen and use a relatively small screen. That reduces the quality of the 2D screenings (as well), since it creates a "hot spot" and darkness around it on the screen.
I use a 900C projector and, with the lamps' output maximum, it would hardly allow for single projector 3D on that screen.

A search within the forum will return more answers.

[Marco Giustini]

and be careful with "high gain screens". As Ioannis mentioned, they'll create a hotspot in the middle. The claim that they increase the light output is debatable at most. On a proper curved frame in the right auditorium they *might* spread the hotspot wide enough so it could be called a success.
But most of the time they concentrate the light in a circular-shaped area in the middle. Yes, if you measure the brightness in that area, you'll see an improvement but if you move away from that area you'll see a massive decrease compared to a lower gain screen.

Overall, the light reflected by a matte screen is subjectively higher than the average high gain screen, particularly if poorly designed/installed.

My personal limit is 1.2 or 1.4 gain. Over that it's usually making things worse.

[Mark Gulbrandsen]

I wouldn't attempt it with an NC-900 unless your screen is like 6 feet wide. And you hven't provided any screen specs, so we have no way to be able to recommend a proper size projector. Ioannis is also correct in that 2 projector 3-D is the best... Preferably stacked projectors because you can generally get the two lenses closest together that way.

[Stefan Scholz]

Marc, sellers have successfully sold NC 900s to unprepared theatre owner, claiming it can do 25 ft screen in scope on 0.8 white (degraded old white). They even claimed by just changing the screen to a 3.0 metallic and purchasing a polarizer attachment, they'd be able run good 3D on the NC 900.
Don't get me wrong, they're compact and rather solid machines, but for the smallest screens only. As you correctly said, even with a high gain silver, 6 ft is tempting in good 3D brightness.
Most of the ones I came across were result of bad consultation, to avoid the possible loss of the deal. The fear, NC 1200 would have resulted in a competitor winning.
I see the same these days, where NC 2000, SRX 510 or Dp2K12C was replaced with SP2K7 lasers. Here, the original equipment of choice in all cases was very well chosen.
What I'm emphasizing on, forget 3D with small machines! Better to invest in proper sound systems.

[Armand Daiguillon]

Ok - no 3D for me.


Thanks all

[Ryan K Georgieff]

I run a NEC NC900C-A with 3d polarizer it's pretty good. is the NC900 a bright projector well no but it's a good projector for it's class. The 3d light lost isn't bad. We have it at about 100ft and the 3d is nice. We have played new 3d movies like "Pacific Rim" and older converted 3d Blu-rays like "Friday the 13th 3 in 3D" which was in red/blue back in the day. The main problem is remember to clean the polarizer as not in use the fans don't run so it can become dusty. second remember to add the distance of the accessory to your projector throw if you shot through glass, and a problem that isn't really the projector's fault is blu-ray players that run 3d content look for the 3d display so if you have a switcher box like the Roland I have then the film won't play because it sees the Roland and not the projector. So you have to plug the HDMI directly in.
if you want pictures I can post.

[Jim Cassedy]

One of the private screening rooms I sometimes work at has an NEC-900c which uses a Dolby 3D system.
Instead of polarization, Dolby uses a form of wave division-multiplexing, which, to give a greatly simplified
explanation, breaks the white light into two wave-groups: "R-G-B" and "R¹-G¹-B¹ ". Prismatic type lenses
on the 3D glasses filter the left/right wavegroups to the appropriate eye.

The advantages of Dolby 3D system are:
1) No need for a special screen.
2) Simple installation, requiring only small (1RU) 3D controller be mounted in the equipment rack;
3) Installation of a small, spinning filter disk inside the projector. (it looks almost exactly like a CD disk)
The big disadvantage is that the glasses, due to the precision filters, are quite expensive and are not
disposable, so some means of collecting, washing/drying & storing the glasses between shows must
the must be accounted for.
I'm not sure if Dolby's 3D system is more or less light efficient compared to a polarized system.
(but I'll bet somebody here knows & will tell me! lol)

That being said, this installation was in a private, 45 or 50 seat screening room that was mostly
used for press & private preview screenings, and I think screen was maybe only 10 or 12
feet wide max for flat & scope. (It was a 'common width' screen installation with movable top
& bottom maskings.) I always thought the 3D there looked pretty darn good on that screen, but
it was rarely used. One of the reasons was that this room is used mostly for studio press screenings,
and we usually gave the attendees a choice between watching the 2D or 3D version of a film that
was released in both formats. Except for "3D-centric" movies like AVATAR, the press people almost
always chose to watch the 2D version- - because they were very often writing notes or checking
messages on their phones or computers during a show - - and the screens on those devices were
impossible to read with the 3D glasses on.

The more efficient of the 3D systems are the dual projector ones. .

Ioannis is correct in that 2 projector 3-D is the best... Preferably stacked
projectors because you can generally get the two lenses closest together that way.

At my current main-gig, we use a pair of stacked SONY SRX-515b
projectors for both 2D and 3D, due to the large size of the screen.
DualSonyProj_2.jpg
The small box at the bottom center is a camera that's part of
the the system that's used to semi-auto align the proj images.

The filters are not automated, and need to be slid in & out of
place manually for 2D/3D shows. This is not a problem for us
since we have full-time projectionists on duty. ( Union Job!)
Sony3DFilter_2.jpg

I don't recall the screen size in this room, but the throw is about
80ft into an old (1916!) auditorium that seats just over 300ppl.
Screen has movable side/top/bottom maskings for 35/70mm shows.

[Marco Giustini]

Don't shoot me but I like the Sony dual stack with the 500 series

[Carsten Kurz]

One of the private screening rooms I sometimes work at has an NEC-900c which uses a Dolby 3D system.
Instead of polarization, Dolby uses a form of wave division-multiplexing,

Are you sure about this, Jim? To my knowledge, there was never a Dolby 3D Kit for the dual UHP lamp NC900. Also, the extreme light loss of Dolby 3D would make it hard to achieve usable 3D light levels on screen sizes beyond TV dimensions.

[Scotty Wright]

At my current main-gig, we use a pair of stacked SONY SRX-515b
projectors for both 2D and 3D, due to the large size of the screen.
The filters are not automated, and need to be slid in & out of
place manually for 2D/3D shows.
[/B]

Is this the Dolby 3D system as well or something else?

[Ioannis Syrogiannis]

Is this the Dolby 3D system as well or something else?

It's all polarization with the 500s and 800s of Sony. (Inside and out. )
On 300 series I have only seen polarization as well, but there might have been other solutions in the past that I don't know of.
With the size of the lens, though, I don't see much chance for a "normal" sized filter wheel in front of the screen.

Dolby was using a filter wheel slipping between the cold mirror and the integration rod, when active. (Great eye separation. A bit demanding on light. Similar technology that was used on 6P laser projectors.)
Sony didn't use an integration rod, like the DLP projectors. Rather a series of filters/prisms.

[Jim Cassedy]

(CORRECTION!)
I originally wrote: "One of the private screening rooms I sometimes work at has an NEC-900c
which uses a Dolby 3D system"

Which made Carsten wonder:

Are you sure about this, Jim? To my knowledge, there was never a Dolby 3D Kit for
the dual UHP lamp NC900. Also, the extreme light loss of Dolby 3D would make it
hard to achieve usable 3D light levels on screen sizes beyond TV dimensions.

Carsten, (as usual) is correct. D'oh!! Apparently when composing that post, I was somehow
completely confusing two different projectors located in two different screening rooms.

The 50 seat screening room with the Dolby 3D system I was referring to has an NEC2000C,
and in that projector, in that room, on that screen, the Dolbyized 3D looks pretty good.

. . and about the dual Sony projector system I posted some pix of, Scotty asked:

Is this the Dolby 3D system as well or something else?

The Dual (stacked) Sony system I posted pictures of, uses polarized projector filters and
glasses. There really isn't any need for any actual 3D "controller", since there is no alternate
eye flashing going on in a dual projector system. Both images are on screen at all times,
which means that even with the polarizing filters & glasses, you're still getting a decent
amount of light on screen since you're starting off with 2X more light to begin with, sort of.

Today's Fun Foto(s)
Here's a couple Siamese Christies set up for dual-3D projection
at another venue I occasionally assist at. (hey, I get around! - I'm
thinking of having "San Francisco's Most Popular Projectionist"
added to my business cards. (lol) Although these aren't in SF)
DualChristie_R.jpg

The images pass through these polarizing filters, which must manually
be moved in & out of place for 2D or 3D. (yep- -it's another "union job"!)
DualChristie_F.jpg


x

[Mark Gulbrandsen]

Installed this 3-D system in place of an Iwerks 15/70 projector. This system kept the theater going for about 8 more years, until the Zion Canyon movie petered out... It worked amazingly well on the 86 foot wide screen.

[Jim Cassedy]

Nice, Mark! - Of course if someone is REALLY serious about putting in 3D, then a 70mm
dual projection system is the way to go- - even though I can't seem to think of anything
released in 70 Dual/3dD in almost 25 years, if not longer. I dug up my old 70mm 3D test
films & I was 'playing around' with such a system not too long ago. I even dug out my set
of old 70mm 3D test/alignment loops.

70mm3dTest.jpg
Unfortunately, while I had several 'left' loops, I can't seem to find my "right"
projector loops. So, I just flipped one the left loops and adjusted the focus
& it worked fine. I was using a set of large polarizing filters from one of my
old Paramount/Stereovision 3D kits, which worked fine for testing.

(Can you still buy 8x10 sheets of good, optical quality polarizing filter sheets?)