Film-Tech Cinema Systems
Film-Tech Forum


Post New Topic  Post A Reply
my profile | my password | register | search | faq & rules | forum home
  next oldest topic   next newest topic
» Film-Tech Forum   » Operations   » Digital Cinema Forum   » Another DLP installation (Page 1)

 
This topic comprises 2 pages: 1  2 
 
Author Topic: Another DLP installation
Ken Lackner
Phenomenal Film Handler

Posts: 1875
From: Atlanta, GA, USA
Registered: Sep 2001


 - posted 05-14-2002 02:58 PM      Profile for Ken Lackner   Email Ken Lackner   Send New Private Message       Edit/Delete Post 
Okay guys, time to tell my story.

The installation of our DLP system was completed late Saturday night/early Sunday morning. I don't know too many of the construction details (like John Walsh told us), but I do know how the system works. I know some of you are very curious, so here goes....

Like John's system, ours is interfaced with the existing 35mm automation. In this case, Big Sky Series 1. There is a switch that we flip to either "35mm" or "BARCO DLP". When we are running a DLP presentation, the server, decoder, and projector will stay on 24/7. The 7kW lamp will stay on all day. (I'm gonna have fun changing that bulb. ) It is the only thing we shut off at night, as well as (I think) the sound cabinet. Looking at the screen, from left to right we have the platter, 35mm conslole & projector, DLP projector, and sound tower with server next to it. I'll try to post pix when I get a hold of a digi cam.

Here's how the system works. Movies will arrive at the theater on DVD from Techincolor. They are then downloaded to the server, because it is much faster to play from a hard drive than from a DVD. The DVDs come with a floppy that has an encryption key that can only be used with that theater's decoder. Everyone's DVD is the same, but each theater has a unique encryption key.

I forget how large the files for Star Wars are, but they took up two of our hard drives. Then they were backed up to another two hard drives. So if the first drive pair crashes, we have a backup. The system is supposed to be able to seamlessly make the transistion.

Once the files are all downloaded to the sever, it's time to build the platter. Yes, that's what it's called, and it's really cool! Just like trailers are shipped in film cans, the DVD's also contain trailers. You select which files you want to show, and then which order you want them shown in. And since not every theaters shows the green bands, they are included as separate files to make it really easy to build your show either with or without them. Once you have the order of the shows programmed, you have to add cues. Even though the Big Sky cue detectors don't work this way, the cues on our DLP system are called inboard, outboard, and center. (I guess if a theater uses the FM-35, Technicolor would program the electronic cues to perform the same functions as the corresponding film cues to make it easy for the operators.) Once all the cues are inserted, you give the platter a name and save it. To run a show, all you have to do is log into the system and select the platter. Then you can fold up the screen and put it away, and all you have to do is press the automation's Start button.

Now for a little about how the projector works. Light enters the projector head through a filter that blocks certain harmful elements of the light and even sends some back into the lamphouse. Because of this, there is no need to close the dowswer every 20 seconds when focusing a bulb. Theoretically, you could project white light onto the screen for hours and there would be no damage to any components in the system. After the light takes its path through the projector head (which is full of twists and turns and details I cannot remember), it reaches the compartment that contains the DMD chips. There are 3 of these DMD's - one for each color. On this chip there are thousands of tiny micromirrors. Each mirror is a pixel. At any given time, each pixel is either ON or OFF. When it is ON, it is reflecting it's color through the lens and at the screen. When it is OFF, it is aimed at some sort of mechanism that absorbs the light (it looks kinda like a heat sink; I guess its purpose is to also absorb the heat). Very fascinating how it works.

They spent several hours Saturday night running test paterns on screen to check the light output and to "file" the electronic aperture plates. How cool is that!? If you over shoot a little, no big. Just take it back a little. Once everything was set up and aligned, it was time to test the system. Did they test it with short clips of a guy and a girl driving around somewhere? Heck no! We got to see Star Wars - Episode II: Attack of the Clones! The movie absolutely was horrible! (See my review.) But as far as the presentation, all I can saw is Wow! You really must see it for yourself before you judge it. Yes, the resolution is 1280x1024. I could not see the pixels, and I was looking for them! The presentation was phenominal in every way. Rock-steady picture; clear, sharp image; rich, bright colors; and sound that will blow you away. There was something artificial to it that I could not quite place my finger on, but I think that was more Star Wars' fault that DLP's fault. I'm really anxious to see a "regular" film shot on film without all the comptuer special effects to truly see how well DLP peforms.

Overall, I am truly impressed. Thank you to the guy from Techicolor, who was the same guy that installed John's system, for explaining everything to me. My only complaint is that we didn't get a "bag of swag."

------------------
This one time, at Projection Camp, I stuck a xenon bulb....


 |  IP: Logged

Aaron Haney
Master Film Handler

Posts: 265
From: Cupertino, CA, USA
Registered: Jan 2001


 - posted 05-14-2002 09:09 PM      Profile for Aaron Haney   Email Aaron Haney   Send New Private Message       Edit/Delete Post 
How can you not see the pixels?!

Are you viewing only from the very back of the auditorium? Is the screen really small? Is it out of focus? Do you need glasses? (Serious question.)

I'm sorry; I really hate to keep harping on this, but I'm beginning to feel like I'm the only person on Earth with two working eyeballs. I've seen DLP many times, and in every case I've found the pixels to be distractingly large, especially on "scope" movies, due to the excessive horizontal stretching. 1280x1024 just isn't enough for the big screen.


 |  IP: Logged

Scott Norwood
Film God

Posts: 7969
From: Boston, MA. USA (1774.21 miles northeast of Dallas)
Registered: Jun 99


 - posted 05-14-2002 09:15 PM      Profile for Scott Norwood   Author's Homepage   Email Scott Norwood   Send New Private Message       Edit/Delete Post 
Ken -- does your DLP setup have sound-sync issues? Every DLP show that I have seen has exhibited weird drifting sound sync problems (off in either direction by a frame or so, varying throughout the show, even when the 35mm prints of the same title looked and sounded fine). Have they finally fixed this?

And, yes, I'd be amazed if the pixels aren't visible from about the eighth row of seats on forward, unless has improved substantially in the last year or two.


 |  IP: Logged

Ken Lackner
Phenomenal Film Handler

Posts: 1875
From: Atlanta, GA, USA
Registered: Sep 2001


 - posted 05-14-2002 09:21 PM      Profile for Ken Lackner   Email Ken Lackner   Send New Private Message       Edit/Delete Post 
I was sitting at the ideal listening position, two-thirds back. That is where I always sit. Picture looked fine. But I will walk the entire auditorium next time to see if I can see the pixels closer to the screen.

There were no sound problems at all.

 |  IP: Logged

Don Sneed
Master Film Handler

Posts: 451
From: Texas City, TX, USA
Registered: Aug 2001


 - posted 05-14-2002 11:56 PM      Profile for Don Sneed   Author's Homepage   Email Don Sneed   Send New Private Message       Edit/Delete Post 
I just installed a Barco DLP/Kinotone Console with Boeing equipment, the picture "Look's Great", the sound was sync, no problem...the light was even all accross the screen, top to bottom. side to side....I saw pixels up to five rows from the screen, beyond that the picture was prefect, 2/3 back....No Problem, perfect picture & sound...I can honestly say this DLP aperture plate was the best filed job I ever done....a click of a couple of buttons & the masking goes right were it's belongs....I loved this feature !!!

 |  IP: Logged

John Pytlak
Film God

Posts: 9987
From: Rochester, NY 14650-1922
Registered: Jan 2000


 - posted 05-15-2002 11:20 AM      Profile for John Pytlak   Author's Homepage   Email John Pytlak   Send New Private Message       Edit/Delete Post 
In my experience, DLP-Cinema pixels are most visible in light areas or whites. "Jaggies" on titles and sharp edges are noticeable further back in the theatre than the pixel structure itself.

Pixel visibility is usually not an issue if you sit beyond the 2 to 4 screen height viewing distance specified for screening rooms in standard SMPTE 196M. (For a 20 x 48 foot image, the specified viewing distance is 40 to 80 feet from the screen). But in many theatres, the audience is forced to sit much closer than this for "sell out" situations.

------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Research Labs, Building 69, Room 7525A
Rochester, New York, 14650-1922 USA
Tel: +1 585 477 5325 Cell: +1 585 781 4036 Fax: +1 585 722 7243
e-mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion

 |  IP: Logged

David Stambaugh
Film God

Posts: 4016
From: Eugene, Oregon
Registered: Jan 2002


 - posted 05-15-2002 11:35 AM      Profile for David Stambaugh   Author's Homepage   Email David Stambaugh   Send New Private Message       Edit/Delete Post 
Ken, thanks for posting all that info. Good stuff, looks like you were paying attention too.

Pixel visibility: By my calculations, if 1280 horizontal pixels are being displayed on a typical 40-foot wide screen, each pixel will be 0.375 inches wide. Now that seems pretty large. Am I correct on this? So the question is, how far back does a person with 20/20 vision have to sit before an individual pixel is no longer discernible, or at least before the vision-processing part of the brain says "I no longer see those pixels".

 |  IP: Logged

John Pytlak
Film God

Posts: 9987
From: Rochester, NY 14650-1922
Registered: Jan 2000


 - posted 05-15-2002 12:05 PM      Profile for John Pytlak   Author's Homepage   Email John Pytlak   Send New Private Message       Edit/Delete Post 
I recall that a normal person with "20/20" vision can discern detail within about 1 minute (1/60 degree) of subtended viewing angle:
http://www.yorku.ca/eye/acuity.htm
http://members.aol.com/MonT714/tutorial/the_eye/acuity.html

The level of illumination (screen luminance) also has an effect.

Some people have visual acuity better than "20/20".

------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Research Labs, Building 69, Room 7525A
Rochester, New York, 14650-1922 USA
Tel: +1 585 477 5325 Cell: +1 585 781 4036 Fax: +1 585 722 7243
e-mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion


 |  IP: Logged

John Moriarty
Film Handler

Posts: 50
From: Cambridge, UK
Registered: Feb 2002


 - posted 05-15-2002 12:12 PM      Profile for John Moriarty   Email John Moriarty   Send New Private Message       Edit/Delete Post 
Opticians reckon that we should be able to see a white line on a black background if the white line is 1 minute of arc at the eye (according to my computer graphics lecturer). Which roughly equates to sitting 3500 timed further from the screen than the width of the line (or size of the pixel). So, if I got my maths right, you should sit about 110 feet from the screen if the pixels are 0.375 inches wide. Hence the 2-4 times screen height is about right (given that this situation should make it easier to see pixels than it would normally be because of the contrast).

This presumes that one pixel can display a whole range of colour.

John

Edit: Please note that I made a mistake, and meant to say 2-4 screen widths (not heights) would be the distance at which you shouldn't expect to see any pixels. See my post further down the page.


 |  IP: Logged

Ken Lackner
Phenomenal Film Handler

Posts: 1875
From: Atlanta, GA, USA
Registered: Sep 2001


 - posted 05-15-2002 12:37 PM      Profile for Ken Lackner   Email Ken Lackner   Send New Private Message       Edit/Delete Post 
I don't know the exact dimensions of our screen, but it looks to be around the same size as a screen at one of my older theaters that I do know was around 46 feet wide. Like I said, I was about two thirds back.

------------------
This one time, at Projection Camp, I stuck a xenon bulb....

 |  IP: Logged

David Stambaugh
Film God

Posts: 4016
From: Eugene, Oregon
Registered: Jan 2002


 - posted 05-15-2002 12:50 PM      Profile for David Stambaugh   Author's Homepage   Email David Stambaugh   Send New Private Message       Edit/Delete Post 
John Pytlak said: Some people have visual acuity better than "20/20".

A lot of people who wear contact lenses, especially the hard lens variety such as gas permeable, are corrected to better than 20/20. I wear gas-perms myself and I'm corrected to 20/15, better than 20/20, as long as there's very good lighting. A person with 20/15 vision can discern details from a distance of 20 feet that someone with 20/20 vision would have to be 15 feet away to see the same details. (I think that's correct)

John Moriarty: So using my example of a 40-foot screen (typical at theaters around here), in scope and assuming the screen is masked to 2.39, the height would be about 17 feet (rounded). With optimal viewing distance of 2-4 times screen height = 34-68 feet. 34 seems kind of close to me, but anyway the math does seem to suggest that the pixels should not be visible from most seats in this hypothetical theatre.



 |  IP: Logged

John Moriarty
Film Handler

Posts: 50
From: Cambridge, UK
Registered: Feb 2002


 - posted 05-15-2002 01:42 PM      Profile for John Moriarty   Email John Moriarty   Send New Private Message       Edit/Delete Post 
Sorry, no, that is just me being dumb. I worked out the optimal veiwing distance based on your quoted pixel size (which I believe is roughly correct) as 110 ft, which is roughly 2-3 screen widths, not heights. For a pixel not to be visible at 34ft would require about 4000 pixels across the screen.

 |  IP: Logged

Barry Floyd
Phenomenal Film Handler

Posts: 1064
From: Lebanon, Tennessee, USA
Registered: Mar 2000


 - posted 05-15-2002 01:44 PM      Profile for Barry Floyd   Author's Homepage   Email Barry Floyd   Send New Private Message       Edit/Delete Post 
I still want to see it on a 100 foot drive-in screen. Then I'll be convinced.

I think Ken has been swayed by the DARK SIDE of the Force.

------------------
Barry Floyd
Floyd Entertainment Group
Nashville, Tennessee
(Drive-In Theatre - Start-Up)

 |  IP: Logged

Ken Lackner
Phenomenal Film Handler

Posts: 1875
From: Atlanta, GA, USA
Registered: Sep 2001


 - posted 05-15-2002 01:55 PM      Profile for Ken Lackner   Email Ken Lackner   Send New Private Message       Edit/Delete Post 
I certainly do not want to see DLP replace film. I am still all for film. All I'm saying is that DLP is not as bad as you may think.

------------------
This one time, at Projection Camp, I stuck a xenon bulb....

 |  IP: Logged

Evans A Criswell
Phenomenal Film Handler

Posts: 1579
From: Huntsville, AL, USA
Registered: Mar 2000


 - posted 05-15-2002 02:16 PM      Profile for Evans A Criswell   Author's Homepage   Email Evans A Criswell   Send New Private Message       Edit/Delete Post 
quote:
I certainly do not want to see DLP replace film. I am still all for film. All I'm saying is that DLP is not as bad as you may think.

It may not be. I say this because last Thursday, I got a new Sony KP-57HW40 TV, a 16:9 set that doubles the scan lines from 480 to 960 when playing NTSC material, and converts the signal to progressive if desired, and can take advantage of the 3:2 pulldown pattern to do a better job at it. I've played some DVDs and I must say that anamorphic DVDs which only have a resolution of 720 by 480 look amazingly good. In fact, they look much better than expected. The screen size on this set is 50 inches by 28 inches and from just 6 feet away (1.4 screen widths), I don't see any scan lines or pixels except occasionally on small sharp objects or on credits. From two screen widths away, these artifacts seem to disappear as well. This tells me that doubling this resolution would allow sitting one screen width away without artifacts, which means that 1440 by 960 might be enough.

I'm not saying these things to endorse digital projection. I like film and its high resolution. I'm saying these things based on my observations of how anamorphicically encoded DVDs look when played on this set. I tried Toy Story 2, which was rendered straight to the DVD resolution, and it looks fantastic from 6 feet away. If I scale that up to a theatre-sized screen, it would be the equivalent of sitting 43 feet from a 30 foot screen, which is a typical width in my area for flat films. At least I have something in my home which can give me something closer to the theatre experience. Mathematically, I need to figure out why such low resolutions can look so good. I suspect it is because of the lower noise in a digital presentation like Toy Story 2 (just luminance and color quantization noise, rounding to the nearest level representable). My experiences with this set don't make good mathematical sense to me yet.

I'd like to get this film to digital thing down to a science so I could prove that a certain film resolution has the same amount of information as a certain digital resolution (given all the characteristics of each).

------------------
Evans A Criswell
Huntsville-Decatur Movie Theatre Information Site


 |  IP: Logged



All times are Central (GMT -6:00)
This topic comprises 2 pages: 1  2 
 
Post New Topic  Post A Reply Close Topic    Move Topic    Delete Topic    next oldest topic   next newest topic
 - Printer-friendly view of this topic
Hop To:



Powered by Infopop Corporation
UBB.classicTM 6.3.1.2

The Film-Tech Forums are designed for various members related to the cinema industry to express their opinions, viewpoints and testimonials on various products, services and events based upon speculation, personal knowledge and factual information through use, therefore all views represented here allow no liability upon the publishers of this web site and the owners of said views assume no liability for any ill will resulting from these postings. The posts made here are for educational as well as entertainment purposes and as such anyone viewing this portion of the website must accept these views as statements of the author of that opinion and agrees to release the authors from any and all liability.

© 1999-2018 Film-Tech Cinema Systems, LLC. All rights reserved.