One of my original ideas is to use angled slats to redirect the light reflection. This is from my personal experience looking at reflections in the room from various surfaces. Some surfaces, even though they are not black, look totally pitch black with no reflection from the screen. This is due to the angle of the surface, there is no light path from the screen to reflect off the surface to the viewer eyes.
To my pleasant surprise I see the concept implemented by Black Room cinema. He calls it optical diffusers. 11 mins onwards in the video link.
This can be used on any surface that is very close to the screen - ceiling, sidewall or floor.
They consist of an array of panels at ~45 deg to achieve this non reflective angle.
In theory, the panels can just be painted black, don’t need to be super black felt non reflective material to avoid that kind of reflection effect that you see on my floor.
However, I realised that there are actually 2 separate and related goals with light reflection management.
First is to avoid glaring reflection from the surface - like my floor. This is seriously distracting and also damages perceived contrast due to the stray reflected light entering our eyes. The optical diffuser would take care of this.
However, there is a 2nd mechanism, and that is stray light reflection off the room and floor, going back onto the screen. This stray ambient will raise the blacks on the dark parts of the image. This is most obviously seen in a ANSI contrast test pattern, with 50% light and dark area.
As they say, a picture says a thousand words.
What about a video? In this case, it likely says a million words.
Projection Dream does good work. Just like Black room cinema, they are less known but their work is 100% solid.
Can read more here.
The TLDR here is that despite JVC projectors being capable of sky high on off contrast in the 20-30k or more, when there is any significant light in the image, the mixed contrast will drop significantly as the light reflects off the room, and raised the black level on the screen.
For optimal black performance in mixed scenes, light control is still very important.
Projectors have limited mixed contrast capability. Top tier DLP like Barco, Christie can hit 1000 ANSI, while Sony and Epson are in the 300-400 range. JVC NX and NZ range was quite weak in ANSI performance 170-200+, despite stellar FOFO.
This is dangerous and controversial area, might upset some JVC fans. My previous projector is a JVC, my current projector is a JVC.
But here’s a photo that shows what I mean. Which one do you think think is the JVC NZ7, which is the Epson LS12000B?
What is happening in that image, is due to reflected light internal to the projector optical system and light engine. Bright areas spilling into the dark areas, washing out the colors, reducing mixed contrast and ANSI.
So projectors have a limited contrast to the image they can put on the screen. We try our best to manage the room light reflection from further degrading it more than absolutely necessary.
Just for kicks, also happened across a screen capture shared by non other than Kris Deering of his personal setup - Lumagen and NZ9.
A veritable black hole indeed.
Anyway, forgot what I was saying with the long detour. The 2 objectives of light control.
The optical diffusers achieves the first, but doesn’t achieve the 2nd, unless you also treat the surfaces Behind the slats to absorb instead of reflecting the light back onto the screen.
I have some preliminary experiments on my ceiling. The angled panels are large slats, and there is definitely still a lot of reflected light back to the screen. Recap - I added some felt strips to try and reduce this.
Long story short, will try some black thin carpet for the floor directly in front the the screen. Just ordered.
That then requires the front power amp to be moved. Will also rewire the front LCR speaker wires and XLR interconnect, maybe change the LR amp, reposition the 5ch amp, various other iterations as I figure out how to place the equipment - processor and amps.
The question is which is more important. On/off contrast or ANSI contrast. The LCOS people will tell you it’s on/off, while the DLP people will tell you its ANSI. The truth is probably that both matter and it’s whether you are watching a dark movie like Batman or a bright one like The Meg.
It’s also why I don’t have an expensive projector. There is no point getting something like a JVC until I bat cave my attic and get rid of the mirrored wall that my daughter used for ballet a long time ago. The LGHU810 I have is very bright, but really needs calibrated MadVR and a low Iris to get dark scenes (< 10 nits) acceptable. However its ANSI contrast is around 600:1, which renders mixed scenes beautifully and with 2700 nits brightness, watching TV programs in ambient light is very good.. You mentioned that “for optimal black performance in mixed scenes, light control is still very important”. Obviously in daylight, mixed scenes will be washed out, but in a reasonably dark, but not completely bat cave environment, I would think that there is not much difference.
I think the best comparator is to have an OLED TV around. That renders dark scenes almost perfectly (almost because some OLEDs have issues with shadows and macro blocking) and with up to 2000 nit brightness, mixed scenes are perfect. I’ve found that using the OLED as a reference to set up a projector for the best possible picture has been useful. However, getting the best picture quality for a movie requires tweaking the projector settings for each movie. Generally I leave the settings for bright movies as the default, but if come across a dark movie, I change the projector settings to compensate. It may be many years or never before we can avoid doing this.
This is from The Meg, which is the torture test of tone mapping 4,000 nit scenes that have been shot. The Lumagen does well here with nice cloud detail, which is usually washed out for most projectors. Even Dolby Vision LLDV doesn’t do very well. I’d post a shot of this from MadVR, but am currently traveling until early August.
