Small room for color grading and sound mixing

[Tomislav Stojanovic]

Hi everyone!

I am new member here, so I hope I am not breaking any rules by writing something that could be considered slightly off topic.

Anyways, I am a colorist from Zagreb, Croatia. Currently exploring an option of building small screening room for color grading and sound mixing. Before contacting all cinema integrators here in Croatia, I was hoping there would be someone here that could help me with some basic questions. I noticed many people here have huge experience with projectors and sound.

First, some general info:
- room for this project would be approx. 5m x 8m, height is 3m (separate booth)
- screen would be 4 m wide in cinemascope (fixed height)
- speakers would be behind the screen, so I need gain 1.0 acoustically transparent screen
- projector should be calibrated to P3 @ 14fl
- Croatia is small market. I can't build something very high-end because it wouldn't make sense economically. So some compromises are necessary and I am aware of that.

My main concerns are these:
- Can I get good enough contrast (primary black level) with small projectors?
- What projector would you suggest - I am looking at smallest DCI projectors available like Barco SP2K-7 or Christie CP2306-RGBe
- Is buying used Barco Xenon and upgrading to laser more expensive than buying new laser?
- What are some screen manufacturers that you can suggest? Looking for some good value for money. Also, does acoustically transparent screen create any kind of artifacts in image, any caveats?
- Do I have enough room height to be able to do this? I need to fit a desk here, and probably just one set of comfortable chairs right in front of this desk.

I will appreciate any help, comment or idea. thanks in advance!

[Marin Zorica]

Hi there and welcome, and yes, you probably wouldn't ever think somebody from same country will answer you

Anyway, based on you're inputs there is no reason you cannot built up room and chose projector that can fit the size. Since, you're market will be cinema, then choice if off course to have real cinema projector in that room!
Something like SP2K-7 would be good choice with using HC lens with it, it will end up higher contrast, and projector has still enough light, 1.0 or lower screen is must in you're case, as silver or anything above 1.0 would just kill all pron's you want to have (contrast and black level).
Screen should be micro-perforated for sure, as since room is small, you are close to is and to avoid artifact. To use non perforated is no go in you're case, because then you cannot place speaker behind it, plus, since if you are doing this for real cinema busines, than you should have real cinema conditions in the room, as 99.9% cinemas in Croatia (if is you're primarily market) has perforated screen! Manufacturer like Harkness screen is available and they can made to fit any size from any screen material they can offer!

I would not advice buying xenon and later upgrading to laser. First, you are buying second hand projector (xenon) which can have some problems later on, plus laser kit are not so cheap. I think laser to go from start should be plus, first, less power needed and much less noise in the room, less heating etc. In last few years I did replaced many xenon units, since all other conversion kit were not so price efficient, and many projector did all ready have some problems, partially dead pixels in engine, accumulated dust and so on.

Some two month ago I installed SP2K-9 with HC lens in small art house, 6m wide screen, micro-perforated and less than 1.0 gain (it was 1.0, but since is 6yrs old, now is less ). Result was great, and even beats previous DP2K-12C used there!

And last for speakers, you could made baffle wall behind, which is cheap for that size, plus if you plan to use something like Genelec.

If you need some kind demo of SP2K or Christie, let me know, we could arrange i, so you can chose base on what you see!

So, you're aproach is good, to chose cinema equipment for cinema based mixing/grading room. I do have setup equipment for many festivals, and mostly problem occur when they play movie in cinema, which is in fact mixed in bathroom/living room studio and color graded on average PC lcd screen.....

[Harold Hallikainen]

Since this is to be used for color grading, I wonder about concerns with metamerism with laser-primary based (as opposed to laser-phosphor) projectors. On the screen, a woven screen is more acoustically transparent (and requires HF rolloff to duplicate the X-curve), but has lower gain (a lot of light passes through the screen).

Harold

[Carsten Kurz]

I think NEC just launched a new very small laser-phospor projector, the NC603L.

Admittedly, something like a Christie 2210 can be bought second hand for very little money now.

[Marin Zorica]

That is point to, but how is reflect on real cinema condition? As for lower gain, that should be no problem with, since there is enough light. But, are there any screen company which offer woven screen? I did have seen some, but they were rated some not special fabricated and thick, which result in very poor flatness.

[Mark Gulbrandsen]

I know two highly experienced colorists on the West Coast and they actually have both Xenon and Laser in their rooms. Many people including these colorists themselves really dislike the coloremetry of Laser. So far the lasers are only there in case the customer or contract calls for it. But they still do their work on xenon, and then use the laser to be sure the work being done is compatible. So overall, xenon still has the purest spectrum, while laser is not as consistent across that spectrum.

[Steve Guttag]

The problem with laser in a review room, especially where color grading will occur...different people see different things. Barco is claiming, with their Post Production software to have mitigated the effects of metamerics but we'll see how the post production people respond to it. I have not, personally, seen the results.

As for NEC in a screening room...their small projectors have really, really poor contrast. Most any (all) of their projectors based on the S2K (.69" DMD) have notable contrast issues, including their LP based projectors. They only rate them at 1600:1 and that is probably generous. Their lens accuracy (for shift/zoom/focus) is wanting too...they don't come back to the same point repeatedly...they are in the ballpark but not precise. On their larger (.98" DMD and larger) they do fine on the above issues...they're slow...but contrast and lens accuracy are respectable.

[Harold Hallikainen]

I THINK the color issues with laser are due to the wavelengths being on the "skirt" of the XYZ filters in our eyes. I believe we judge color by the ratio of the amplitudes out of the filters (using an electrical analogy). The shape of the filters and their center frequency varies person to person. However, our brains calibrate out these variations through our experience with broad spectrum light (typically from the sun). If we, instead, use narrow spectrum light that is on the skirt of the filter, minor variations in the shape of the skirt or the center frequency can result in large variation in the output of the XYZ filters, varying the ratios and our perceived color. I think laser would work better if the frequency was at the center frequency of the XYZ filters where the slope is zero, so person to person variations would result in minimal filter output variation. But, it may be difficult to get lasers at those frequencies.

[Steve Guttag]

I just put in a collection of Barco S4 (and an NEC S3ish...NC3541L). The Barco S4 are now using, what looks like, 3 primary values while green has maybe 2 primaries? I'll have to look at the display (Qualif Spectro) again...it looked like there were three red spikes in it. I know when I tried a USL PCA-100...it went nuts trying to come up with a color and would ping-pong between two coordinates. The NEC is RBB laser with a green phosphor wheel...that one is easy to color calibrate with single primaries...except green which has a "blob" instead of a color point. When looking at the corrected color in the DLP program...there seems to be trickery going on there in the TCGD...but it measures (and looks) fine though maybe a bit colder than xenon or RGB laser.

[Marin Zorica]

I agree with facts about laser projection cons. But, since that will be review room, should it be as more as possible close to cinema real conditions? For example, all new instaation in cinemas are laser now, even old cinemas upgrade are going to laser...

Anyway, I would ways gave my wote for example DP2K-12C xenon, 0.98 dmd and much light efficent than any smaller 0.69 units. But, as I told recently using SP2K-9 with HC lens in same room and screen were 12C were, relly did proveaser in some condition (low gain screen) can do relly good.

[Marcel Birgelen]

We do color grading and audio mixing in our screening room and have been looking around for a replacement of our aging Barco DP4K-23B with HC lens for a while now. We replaced the Dolby CP850 and Alchemy IMS with a Dolby IMS3000 combined with a Q-Sys system for flexibility in audio routing last year and a half. We've been looking for a Barco S4 for a while now but colorists are VERY reluctant with laser and some actively refuse to work with them... So, we're now trending towards Christie, who still offer xenon DCI projectors.

We've actually been looking at direct view solutions, we're now in contact with a Chinese company that claims to be able to deliver a solution that is both DCI-compliant, 4K and fits the size of the room. Still, we haven't figured out how we're going to do audio "right" in case of such a screen. First demonstrations of non-DCI compliant systems on this scale have been pretty impressive, especially regarding the color range of those systems, but DCI certification has been the biggest hurdle.

If you're not bound by DCI certificated equipment, then you have far more options to go by, also on the projector side. Still, it's a good thing to try to work with the stuff that will eventually also be in the cinema.

[Tomislav Stojanovic]

Hi everyone!

Thanks for all your suggestions. Marin, I found you while searching for people doing cinema installations in Croatia, so I will give you a call soon :-)

I was told it was a bit complicated handling Xenon bulbs. Also, Xenons are being replaced by lasers, so it is definitely a factor. Metamerism is probably issue that Barco will have to solve by creating new CMS for matching or giving alternative target coordinates. New coordinates is probably what they will be doing for "xenon emulation" mode. I just hope it would be possible to copy these coordinates to non-P projectors. I guess Barco postproduction projectors are much more expensive? Also, I noticed flicker with some Xenon projectors. Is that a sign of bad lamp or inherent to this tech?

Currently I am using Eizo Prominence CG3145 for grading. It is high end grading monitor. It also has a problem with metamerism but mostly with white. It was never a problem once calibrated using perceptual match approach (matching WP manually to calibrated broad spectrum backlit monitor). With laser (if I understood correctly) the problem is with both white AND primary colors... So it is not as easy as creating alternative white point.

If you're not bound by DCI certificated equipment, then you have far more options to go by, also on the projector side. Still, it's a good thing to try to work with the stuff that will eventually also be in the cinema.

Interesting! Do you know any specific models? I heard about Espedeo Supra 5000. I will try to find it here in Croatia to check how it looks.

[James Gardiner]

Espedeo Supra 5000, from my understanding it uses some type of colour wheel trickery, but it's not a colour wheel. It does not have a DMD for every colour.

Barco, and Christie, from my understanding, use the same laser diodes, so I cannot see one being better than the other. Barco has done a lot more Post-Specific work, plus I would imagine the POST-PROJECTOR is only available in 4K, as that's the standard for mastering now. And is also likely a phospher-based unit as it would be less exposed to the metameric problems.

But if price is no object, I think the Barco would be the unit to get. They have spent more time perfecting their product for POST from my understanding.. (Over Christie, who only have primary laser RGB, which is likely not as suitable as Barco Smart laser that has phosphor wheel in use. (Slightly less power efficient I hear)

As laser is the only choice for cinemas going forward, mainly for power savings over xenon, it appears ridiculous that colourists refuse to work with the technology that is the only way forward. Yes xenon does not look like a laser, but they insist in using xenon is very problematic.

They better get onboard with Laser if you ask me, and figure out how they can mitigate the issues they have. This new Barco POST-LASER unit. I would like to hear more about how it deals with the issues colourists have.

[Steve Guttag]

The reason colorist don't want to work with lasers..and it is valid...there is no way to trust the results. You bring two colorist into a room with xenon light...they'll agree on what it looks like...bring them into a laser system...they won't. It isn't as simple as "well that's what it is in the theatres" because they don't even know what they are looking at and can't trust their own judgement on what they are seeing. It is a valid argument. If they judge on xenon...even if shown on a laser, at least it will be uniform and the person won't be influenced by their own metamerics in color judging.

Let's say I see laser projection as a bit too red so when I judge the image, I start shifting things green..it will only look correct for people that see the laser projection as I do and it will be hyper green for those that see laser projection as more green. Conversely, if judged on xenon with actual color, everyone's metamerics remain the same and yes you'll still see the image tinted as you perceive them but nobody gets the exaggerated version.

This is a laser projector company's problem.

The Post Production version of the Barco laser projectors is strictly software (with respect to metamerics and the ability to mess around with color space). ANY SP projector, with a suitable license and running on firmware 1.8 and later could generate the metameric correction files (search the Barco site for a white paper on it). Barco DOES have high-contrast projectors, the SP4K-13HC and SP4K-27HC which post houses are more likely to use as they can get darker-darks with an approximate 5000:1 contrast ratio achieved from an improved light path and ultra high contrast lens (it is more than just the lens).

In my opinion, there is a notable improvement when one gets to 2300:1 and stark improvement at 3000:1 (typical HC lenses on laser projectors). The overall picture looks notably better. While the 5000:1 does look better, it just doesn't seem to have the dramatic impact that you'd expect...perhaps because of how films are mastered? If they were to actually presume theatres had 5000:1 contrast ratios, black detail would be lost...even for theatres that set up their equipment properly. Anything below 2000:1 (xenon 4K, all lamp based .69" S2K and NEC .69" LP) look notably worse in the contrast department (one need not have an eagle eye to notice that there are no blacks...just greys

[Marin Zorica]

I agree on above about laser disadvantages, but in near future we will be off xenon unit's and leave to laser. Not my personal like too, but, that is market, and cinema owners like when they cut maintance and electricity cost to half.... As you stated for Post version of SP's, still investing in SP is good way to go and later invest in post licence.