Barco LS4K

[Fernando Caldeira]

Hello all,

Has anyone seen or worked with the new Barco HDR LS4K-P?
Is it as good as they say it is?
Is there a contrast ratio number out?

Thanks
Fernando

[Leo Enticknap]

I saw it on display, and a demo of it working, at Cinemacon earlier this year.

The demo I saw was of a restoration of Godzilla vs. Mechagodzilla: 1970s dye-coupler color, no matter how well captured and post-processed, is not going to put any ultra-high contrast display technology through its paces, so I didn't get an objective sense of how much of an improvement it is on the 1.38" chip SP4Ks with a high contrast lens in front. Subjectively, it looked very good to me, but I'd need to have seen the same movie projected from, say, an SP4K-27BHC, to have any idea of whether it's a significant upgrade from it.

[Steve Guttag]

I'd think any contrast ratio that they could publish will need to have an asterisk with it. Contrast Ratio for DCinema has had to be one of two numbers. The feel-good number is to project full white, measure...then project full black, measure. The light is not allowed to be modulated. These are the CRs that get you from 1600-6000:1 (sequential contrast). The real contrast ratio would ANSI contrast and those are much worse...in the 100s:1 ANSI CR uses a 50% checkerboard pattern. You measure the center white square...then flip the squares black for white and measure again...so the entire optical system is excited and you have plenty of light scattering about (it also will let the room itself, and its light reflections, degrade the measurement).

Light Steering takes advantage of the fact that rarely does the entire image need to be full bright (and if it is, there aren't darks to compare and your eye's iris will shut down to not resolve the darks being blown out). So, if we can recapture light that would, ordinarily, need to be reflected to the heat sink for the dark portions and redirect it to the lighter portions we can have brighter whites while keeping darker darks. If you were to run an ANSI Contrast test, it is going to test similar to any other high contrast projector because with a 50% checkerboard pattern it doesn't get to reclaim anything.

I think they're going to have to have some sort of qualifier to put up whatever number they associate with it as it will be equivalent to. Mind you, home theatre projectors have been modulating their light for years to get their fanciful claims of a gazillion to 1 contrast ratios. The same way DCPs have to have a frame of image data for every frame of video, we also don't get to modulate our light.

My personal opinions are, if you watch content on a projector that has about 3000:1 CR (sequential) and one that has 5000-6000:1, are you not going to notice much difference. If I were to set up two theatres, one with each and you could walk between the two to watch the same content, you'd be hard pressed to say which was witch. With an A-B in the same room with zero or near zero delay between comparisons, you will see it but the real world isn't like that. People just don't notice things getting that much darker, after a point until you finally make it from dark-grey to black.

The other aspect of the Light Steering projector is that it is going for 300nits or about 87.5fL. This, dramatically improves contrast ratio on its own. With a 48nit (14fL) white level, you've see up a tough contrast ratio. To get 2000:1 with 14fL, you need to get your dark level down to .007! How good is your meter to measure that one? Even at 87.5fL, you are only up to .044fL with a 2000:1 CR. So, getting a projector that has an optical path that can get up to 5000-6000:1 before any sort of light manipulation is going to go a long way to having the darks remain dark at the elevated level.

Personally, think that going for 300Nits, at this stage, is the wrong move. In order to get the white level up that high they have to severely limit the screen size so it will not be in your biggest theatres. Had they gone for a more modest 108Nits (Dolby Vision), the same technology could be used in large theatres and with a growing content list of movies mastered with that sort of white point.

In the end, they won't be able to touch emissive screens (LED) because their off is 0 and their on is whatever the LED is capable of. So, a real 300Nits with a contrast ratio that is limited by the ambient lighting of the auditorium, not the light source. That is where you will see HDR get mainstream in cinemas. The question is when the technology will be affordable enough to support the purchase combined with the movie industry's behavior to theatrical attendance.

[Stefan Scholz]

It is all about specs on paper.
Projection has limits, and no projection will be capable of true High dynamic range images.
The re-reflections from the room limit your contrast ratio. It eventually is possible to design a matt black room, with matt black seating, and being alone in that room as a measurement engineer, switched off emergency lighting, you might read a decent contrast value.
The moment the lights are turned on, the measured contrast diminishes. Then, a stadium full of patrons, each with a glossy, reflective face, the re-reflections limit your contrast significantly. A floor curve of old school rooms helps, but is rarely found.
The main reason I see for raising light levels on screen is in the fact, that 50 nits (cd/m2) or in imperial units 14 fl, is on the border of night vision for most humans. Meaning limited color rendition. All cats are grey at night. Just going above that, does really help to make movies look great. I doubt 300 nits or 87.5 fl will bring the great wow effect. It's brighter.
Another factor of human vision is the limited range of contrast perception within a given state of accomodation to light. Our eyes adopt to the current brightness level by trimming the iris. Still the receptors have the same limited range they can capture. The dynamic range of a computer monitor is higher, than the range our viewing mechanism can resolve.
Still, in projection there is a need for great native machine contrast, the very limited dark capabilities of early generation digital projectors have never been acceptable. I have found Kinotone brand Barco based 4K projectors, where we were able to measure an actual contrast ratio in checkerboard patters below 40:1, it might have even been 25:1. The machine was sold like this, complaints made, but nothing happened.
The moment the warranty period was due, the manufacturer service had a hint "about too low contrast", but also knew "out of warranty".
This has not been the only projector with such a problem I found in the field, but the one I measured due to curiosity.
With Barco made ones, the images always looked better, still early 4K never really had satisfactory contrast on any manufacturer.
Today I always aim for the Ultra High Contrast lens option on the 4K projectors, these also offer a better overall visible "convergence" and resolution over High Brightness or Enhanced Contrast versions of the lens. Pair it with 75/ 80 nits/ 25 - 27 fl on screen (the upper value of the old film standard for 35 mm), and there's a significant benefit perceived and noticed over competing venues in the market field.

The Dolby Vision approach seems to be a good compromise, in well designed rooms. Full color rendition for the viewing mechanism, large enough screens possible.
Their illumination brightness seems to recreate the initial brightness standard for 70 mm roadshow in the 1960's.

[Jim Cassedy]

The venue I'm at is installing one of these LS4K's later this week.
Also a new screen.

[Carsten Kurz]

I guess this is a mastering/grading facility?

[Jim Cassedy]

I guess this is a mastering/grading facility?

No- - It's replacing a dual SONY SRX-515b in a large theater auditorium.

[Scotty Wright]

No- - It's replacing a dual SONY SRX-515b in a large theater auditorium.

Does Barco have a 3D solution for that projector? Or do you have to put in a realD system and high gain screen? (We are in the year of Avatar 3 now after all).

[James Gardiner]

DCI/SMPTE have been doing a lot of work on what should be the next cinema standard for minimum and peak luminance. The 300nits would have been selected for a reason.
I do question why a 105nit, or peak luminance that is compatible with numerous custom/better than current cinema specs, was not also given an interim acceptable specification. But DCI is well known for not wanting to approve any more options for distribution than is needed to keep production costs minimal. (Avoid explosion in deliverables)

With all the technical real world challenges in the new DCI-HDR addendum, some level of license was always going to be needed to settle on a new set of numbers.

If Barco has landed a projector that can do 300nits already. That looks like it's the new target that everyone will have to eventually make projectors of that capability. Manufacturers can now optimise the manufacturing and investment and stop making every better technology at ever increating costs. The industry is not up for that type of effort going forward. A line in the sand was needed, and we have one now.

Yes, it is still very problematic in terms of minimum brightness level and environmental factors. That's for each region to sort out and to get the best results they can within the legal requirements or design of the room that has more character than mat black walls/seats.

[Carsten Kurz]

No- - It's replacing a dual SONY SRX-515b in a large theater auditorium.

I read an interview where they say that a single LS4K-P supports screens up to 18m wide - when the screen has a gain of 2.9(!). Wondering how that works out...

From a marketing perspective, Barco of course wanted to surpass Dolby Cinema by numbers. Now the 300nits figure of course is not a 'full screen 300 nits', but a 'local 300nits', means, that peak luminance is limited to a local spot of so far unspecified dimension anywhere on the screen - like a visible light or the sun in a scene.

[Marco Giustini]

I read an interview where they say that a single LS4K-P supports screens up to 18m wide - when the screen has a gain of 2.9(!). Wondering how that works out...

How can it work out... badly! I'd hope that cinemas have learnt by now that high gain screens are bad but I am not holding my breath.

[Jim Cassedy]

Install began on Monday. They ripped my entire booth apart. I can't find anything.
The new machine has a larger longitudinal footprint than the former SONY proj's
it is replacing. Unfortunately, all the projection equipment is on a platform about
4½ft high. They had to remove the guard rail to do the proj swap, and they hadn't
put it back yet when I had to leave unexpectedly on Monday. But from what I could
see, there will be only be about 14in, if I'm lucky, between the new BARCO's backside
and the guard rail on the platform. I'm not a very big guy, but I'm not sure how anyone
is supposed to get squeeze by there to get to the Film-Tech Cinema Systems film proj with with 70mm reels. I
guess I'll have to figure that out by Thursday morning, since we have a have a major
70mm engagement in there starting this week.

Also, unfortunately, I had to leave the theater unexpectedly around noon on
Monday and I wound up spending the rest of the day & most of Monday nite in
a hospital emergency room, and although I'm at home now, and I'll be perfectly
OK, I've been passed out for most of today recovering my my nite in the E-R, so I
have absoloutely no idea what progress has been or what state my booth is in. I
assume they're almost done, since I see that they've sent Deluxe and a couple of
our other regular distributors the new server certs so that they can issue new KDM's.

[Leo Enticknap]

Sorry to hear about the ER. My boss and a co-worker were involved in your LS4K install, and so I'm sure I'll hear the rest of the gory details when I next see them! The SP4K-XXB chassis (which, if I remember from seeing it at Cinemacon correctly, the main LS4K unit shares) is significantly longer than its Series 2 predecessor, and that has caused problems in a couple of SP4K-B installs that I've done.

[Jim Cassedy]

<edited> The SP4K-XXB chassis is significantly longer than
its Series 2 predecessor, and that has caused problems in a
couple of SP4K-B installs

I knew I was in trouble when the FIRST thing one of the installers said to me when I
showed up in the booth today was "How are you going to do the 70mm in here?"
I measured appx 14⅓ inches clearance between the back of the BARCO and the
safety railing on the platform. I'm guessing there's going to have to be alotta "reel
rolling" to get to the 2nd film proj. The new projectorthingy is also taller. I can't even
SEE the 2nd JJ from most of my booth right now.


I'm sure everyone knows what they're doing, but right now my booth looks like an
explosion in a cinema parts & tools factory. We're less than 24 hrs away from a big
70mm show, and so far, a lot of my audio system has been decimated, the masking
control isn't working, and I'm not sure about the curtain. The lamphouse exhaust
system, (which I need for 35/70) is not in operating condition, the rewind bench,
which had to be moved as part of the projector swap, isn't functioning. (and I've
got six friggin' full 70mm reels someplace that will need to be rewound. . possibly
by hand, before tomorrow night.) The film projectors, which I had to make major
longitudinal and vertical adjustments on for the past two off-aspect ratio film
shows are still not back where they need to be, and I can't work on them because
there isn't enough room for the projectorguys and me to all be working in the same
place at the same time. - - and they're starting to work on calibrating the BARCO,
so I can't have the booth lights on, or put an RP-something-or-other alignment loop
on screen, and the PA audio board is also in a total state of destruction.

(Forgive me, but, I'm actually beginning to wish I had stayed in the hospital)

[Steve Guttag]

I wonder how they got around building code. There is supposed to be 30-inches between a film machine and any other boundary except on the lens side. For machines that are side-by-side, their 30" boundary may overlap (you don't need 60" between machines. California, I'm pretty sure, adopts the International Building Codes. This one, in particular would apply:

409.2Construction of projection rooms.


Every projection room shall be of permanent construction consistent with the construction requirements for the type of building in which the projection room is located. Openings are not required to be protected.

The room shall have a floor area of not less than 80 square feet (7.44 m²) for a single machine and not less than 40 square feet (3.7 m²) for each additional machine. Each motion picture projector, floodlight, spotlight or similar piece of equipment shall have a clear working space of not less than 30 inches by 30 inches (762 mm by 762 mm) on each side and at the rear thereof, but only one such space shall be required between two adjacent projectors. The projection room and the rooms appurtenant thereto shall have a ceiling height of not less than 7 feet 6 inches (2286 mm). The aggregate of openings for projection equipment shall not exceed 25 percent of the area of the wall between the projection room and the auditorium. Openings shall be provided with glass or other approved material, so as to close completely the opening.