:mirror-like screens" ? - bright room setup Q.

@te36 The 52ALV does not have 3500 lumens, real brightness depends on the mode used.
Here is a review of the 51ALV which is "rated" at 3000 lumens, with lumen measurements:
https://www.projectorcentral.com/Optoma-UHD51ALV-review.htm

The brightest mode, Bright, has a green tint as many other projectors do.

Brighter projectors are available, such as the Epson TW7100 (EU)/HC3800 (US).
Review with lumen measurements for the previous generation Epson, HC3700:
https://www.projectorcentral.com/epson-3700-review.htm

The kind of screen you're referring to are called ALR (Ambient light rejecting).
There are several types, here are two articles with details:
.https://www.soundandvision.com/content/how-do-light-rejecting-screens-work
https://www.soundandvision.com/content/finding-sweet-spot-alr-projection-screens

Both angular and retro reflective ALR's cannot be used with UST or short throw projectors. Minimum recommended distance for many brands is x1.5 the width of the image (throw) or higher.
The Optoma's 52ALV throw range is x1.21 – 1.59. The Epson TW7100 throw range is x1.32 - 2.15:1.

However, projectors are not TV's and, with some exceptions, are not suitable for daytime viewing with lots of ambient light.

No matter what projector + screen setup is used, if there is too much light in the room the image will be too washed out. Especially the dark parts.
With an ALR the bright parts will loose less detail than the dark parts, but still unacceptable for general use. The only thing an ALR screen setup with lots of light in the room ca be used for is broadcasts that you don't care that much about the loss of quality, such as sports,day time TV, or a very bright cartoon/game (i.e. Rocket League).





Getting a curtain/blinds that block the light is a start.
With light from windows blocked, dimmed lights, and strategically placed lights that do not hit the screen directly things can be improved. Some are fine with this result, others aren't.


Long throw ALR farbrics can display hotstpots/sparkle under certain conditions: projector is too bright, too close, brightness of the projected image, quality of the fabric.
Long throw ALR's are different from UST ALR's.
UST ALR's should not have a hotspot/sparkle and have good viewing cone (except for Fresnel type fabric).

In the EU there are companies that sell ALR, Elite Screens, Hivilux, and others.


What type of space is the projector/screen setup going to be used for? Is it a media room, commercial space?
What type of material will the setup be used for, movies, games?
Is 4K required?
What are the room dimensions?
What is the source of the lights?
What is the budget?

Thanks for all the great info.
I wanted to go for DLP after 20 years of only LCD projectors. White pixels without color borders for a change, especially when projecting windows desktop. So no Epson this time. Want to try 4K, even though i think the biggest benefit is just to get rid of the screendoor effect due to the vibrating panels. And 3D required.

Room is just small basement living room (aka: not darkened for home cinema), only 2 meter high (low ceiling), 3.5 meter deep. Acording to projectorcentral, for 90" diagonale, i'd need the projector to be at most 3.20 meter away, so maybe i'd put it even a bitcloser to the screen, 2.60 meter or so (from lens).

I can control the light, but of course its harder trying to set up lighting to not hit the screen, and preferred viewing in this case is to be as bright a possible most of the time.

So far i've only used white walls, so no good experience with different screen materials.

From your description, angular ALR sound like better hitting lower viewer location than retro reflective. With screen desired to start from ceiling down, the 1/3 height of retro reflective would be too high.

Price is a matter of how much more i get from the screen. E.g.: Elite Screen CineGrey 3D seems to be half price of CineGrey 5D. Have you seen the difference ? When yould it be worth to buy up to the 5D in your opinion ?

With long throw ALR's it's not recommended to go under x1.5 throw range (with of the screen).
Even with throw range over x1.5 there will be a hotspot and sparkle in the center of the screen.

Examples with a projector at x1.15 and x1.5 throw ranges on Cinegrey 3D.
https://www.avsforum.com/forum/23-screens/3094730-picking-screen-budget.html#post58659830
https://www.avsforum.com/forum/23-screens/2122202-aeon-elite-screen-cinegrey-3d-9.html#post58568560
https://www.avsforum.com/forum/68-d...e-cinema-projector-review-3.html#post57673262

A better material, a longer throw range, a dimmer projector, and a dimmer projected picture can help mitigate the hotspot/sparkle.
Some ALR screens have a lower viewing cone. For the Cinegrey 3D it's 90 degress (45left, 45 right).
https://elitescreens.com/kcfinder/u...s_Screen Material/CineGrey3D_gainChart(1).jpg

If the length of the room is 350cm, the depth of the screen and projector need to be taken out to find out the usable distance.
The screen could be ~5cm deep.
The Optoma 52ALV dimensions are: (W x D x H) mm 392 x 281 x 118.
So 5cm+28.1+10 (for cables at the back of the projector)=43.1cm
That would be ~306cm to work with.

This site can be used to calculate distances with most projectors:
https://www.projectorcentral.com/Optoma-UHD52ALV-projection-calculator-pro.htm

http://screen-size.info/

The throw range on this model is x1.21 – 1.59. With x1.59 throw range there is definitely going to be a hotspot.

A matte negative gain screen will produce a worse image than the ALR since the fabric absorbs light and spreads the result uniformly, it does not reflected it like an ALR.

An alternative to the Optoma 52ALV would be the upcoming Benq TK850, the bright version of the W2700.
https://www.benq.com/en-us/projector/home-entertainment/tk850/specifications.html
It has a short throw range of x1.13 - 1.47.

Hivilux is based in Germany and has a very similar ALR fabric (Hivilux Cinema 5D (ALR)) to the Elite Cinegrey 5D. The 5D is more aggressive the 3D.

An UST projector and an UST ALR screen are also an option, as shown in the last video above.
UST ALR screen will not have hotspot/sparkle (unless Fresnel type of fabric).
UST ALR's will do best in rejecting light coming from above.
https://www.avsforum.com/forum/23-screens/3094726-ust-screens-alr-vs-clr-vs-fresnel.html



All of this being said, the main issue is that with too much light in the room, the image will be washed out. It does not matter what projector+screen combo is used, too much light will overwhelm the picture.
Even with dimmer lights, would you watch a movie on an image that has it's dark parts washed out? Maybe a sports event, but not anything serious.

Look at the dark parts of the image in the examples with ALR screen in ambient light.



It sounds like a TV would be better suited for this environment.

ALR vs matte screen makes sense where there is some sort of light in the room. In the dark, not so much.



The second example looks better because of the positioning of the lights. But if you look at the black detail, it's still not great.

Regarding screens.
It depends on the price you can get, the region, custom duties, etc.
Options would be:

Hivilux Cinema 5D (ALR) - a user was given a quote for ~500$ for a screen with this fabric.

XY screens - contact them to get a quote; They have different ALR fabrics for long throw projection.
Thread:
https://www.avsforum.com/forum/23-screens/3005728-xyscreen-comparison-review.html

Vividstorm ALR
https://www.amazon.com/VIVIDSTORM-Ceiling-Tab-tensioned-Electric-120-inch/dp/B07KNZHS6F?th=1
Some users have received units with indentations. If you can get a good unit, that is great price. Don't know if you even need a drop down screen.
https://www.avsforum.com/forum/23-screens/3065466-vivid-storm-tab-tension-grandview.html

If a wooden frame can be built, ALR material is available for under 200$.
From Elite:
https://www.amazon.com/Elite-Screens-Designer-135-inch-ZRM-135H-CINEGREY/dp/B01CX3AILC?th=1
And Carl's:
https://www.amazon.com/Carls-Ambient-Rejecting-Projector-Material/dp/B018J2EH3G

I personally went with Cinegrey 3D. The hotspot is bad enough with the 3D, with the 5D it would have been worse. The 5D does have better light rejecting capacity. Carl's ALR is even more aggressive than the 5D.

Another budget option is paints. This will allow for the projector to sit closer since I don't believe there is any hotspot. Can be sprayed or rolled.
Don't think that any paint can match an ALR screen though.
The sub thread:
https://www.avsforum.com/forum/110-diy-screen-section/




Not too familiar with budget UST units. They are fairly new. I think I saw a recommendation for UST PJ+UST ALR screen for ~2$k, but can't find it.
Check out the sub forum here or make a new thread for info:
https://www.avsforum.com/forum/68-digital-projectors-under-3-000-usd-msrp/

LED strips around the screen are a bad idea, it looks bad, and is distracting. It will probably washout the picture more than it will do to improve perceived contrast.

bdht said:

One thing you can do for alr that requires some extra planning is use a very bright projector and a matte dark gray 0.4 gain material. Projectors like the barco/pd f30 or dpi dvision/mvision projectors take 2 lamps and dependong on the color wheel can get up to 7000lumens. They use the 0.95 ti chip, have good color gamut, color brightness(at least the vizsim rgbrgb wheeled ones), have great lenses, but will generate alot of heat and pull alot of power(upto 1kw with both lamps on high). Using a dark grey low gain screen will fight alot of ambient light without any gain artifacts so you can have a shorter throw.

Click to expand...

That sounds just a tad less expensive than buying the town-house next door, tear down the wall toward it and install rear projection.

Given how i only have space for a 92" screen in this setup, anything high-end is IMHO inappropriate. If the stupid industry was willing to take my money, it would simply sell me an 86" 3D capable TV screen and i would not even have to go for a projector. Maybe its still possible to go for one of the 120 Hz capable 86" screens with an external HDMI 1.4 3D to 120 Hz frame sequential 3D converter boxes, but not sure if those are still available.

Realistically the main issue is going to be that the best solution short of a 3D TV in my case would be an UST projector with an UST screen, because those can be built to reject a lot more environmental light than non-UST screens (as i learned in this thread, thanks). Except that the UST projectors will still take maybe one more generation to be where i would want them (do not want to buy a UST projector unnecessarily bulky because of built-in speakers).

I really wanted to try DLP for the first time in 20 years, and the UHD380x looks like a good choice for my situation, and i did hate the misalignment of the pixels in the LCD projectors i had/have. But the TW7100 does of course look like an excellent choice, especially because i could also lazily keep the existing off-center mount-point i have right now due to its flexible lens-shift *sigh* *sigh* *sigh*.

I am getting more worried about the hot-spotting, so i will definitely take it slower with the screen choice.

noob00224 said:

A matte negative gain screen will produce a worse image than the ALR since the fabric absorbs light and spreads the result uniformly, it does not reflected it like an ALR.

Click to expand...

I guess/hope "worse" just means "less light", but otherwise it should also be "no-hotspots", so effectively, a matte 0.8 gain screen might actually be the best solution in my situation (unavoidable room light), right ? Especially if i wanted to stay lazy and keep my existing mount, e.g.: you wouldn't want to see what ALR does when you have an off-center moint point. And its also below the upper edge of the screen, so any ALR "reflections" would go the wrong way.

I guess i can paint a 0.8 matte screen myself, something like buying a 50 Euro white screen and fully matte wall paint. Worked pretty well for 1.0 matte 20 years ago for me.

I am trying to figure out if there is a formula for me to decide on the ideal negative gain. I guess i could kill a some ink on my printer and produce some sheets of different grey tone papers to test, and then overlay that with a projected greyscale picture from a computer to simply visually judge the result (blackness of black and brightness of white). Which also means i should first try to optimize my room lighting, aka: first buy / install some spotlights, and then figure out the right negative gain.

te36 said:

I really wanted to try DLP for the first time in 20 years, and the UHD380x looks like a good choice for my situation, and i did hate the misalignment of the pixels in the LCD projectors i had/have. But the TW7100 does of course look like an excellent choice, especially because i could also lazily keep the existing off-center mount-point i have right now due to its flexible lens-shift *sigh* *sigh* *sigh*.

I am getting more worried about the hot-spotting, so i will definitely take it slower with the screen choice.



I guess/hope "worse" just means "less light", but otherwise it should also be "no-hotspots", so effectively, a matte 0.8 gain screen might actually be the best solution in my situation (unavoidable room light), right ? Especially if i wanted to stay lazy and keep my existing mount, e.g.: you wouldn't want to see what ALR does when you have an off-center moint point. And its also below the upper edge of the screen, so any ALR "reflections" would go the wrong way.

I guess i can paint a 0.8 matte screen myself, something like buying a 50 Euro white screen and fully matte wall paint. Worked pretty well for 1.0 matte 20 years ago for me.

I am trying to figure out if there is a formula for me to decide on the ideal negative gain. I guess i could kill a some ink on my printer and produce some sheets of different grey tone papers to test, and then overlay that with a projected greyscale picture from a computer to simply visually judge the result (blackness of black and brightness of white). Which also means i should first try to optimize my room lighting, aka: first buy / install some spotlights, and then figure out the right negative gain.

Click to expand...

Although the literature for ALR says that the light from the projector is reflected at an equal angle and the viewer's eyesight needs to be in the path of this reflected light, I found that the image is fine if the eyesight is higher, even above the center of the screen.
If I move the viewing position left/right the hotspot follows, so I'm not sure what effect mounting the projector off axis will have.
Different ALR materials can behave differently from the Cinegrey 3D with regards to how the hotspot will appear to the viewer at different viewing positions and placements.


The UHD380x can't be under the top edge of the screen, since the offset is 105%, which means the center of the lens needs to be 5% of the height of the screen, above the top edge of the screen.
The only way to do that would be to tilt the projector upwards and use keystone. Keystone is software and will degrade the quality of the picture.


I don't know how much printing different greys on paper will compare to paints or screens. Some screens have multiple layers, and I'm not sure, but paints would also behave differently than grey paper.


Just like it's said in this thread, a grey matte surface will not reflect ambient light and reflect it at the same angle like an ALR, but only absorb some of it and reflect the rest at ~160 degrees.

A more detailed explanation in the thread below. At the bottom of the page there are four scenarios with different types of lightning on a Cinegrey 3D and a piece of white paper. There is also a link with more examples with this setup at the bottom of the first post. A grey matte screen will behave more like the white paper than the ALR:
https://www.avsforum.com/forum/68-d...projector-use-ambient-light.html#post58810778

Additionally paint mixes exist that have some interesting properties, and not behave just like a matte grey surface:
https://www.avsforum.com/forum/68-d...on-5050ub-6050ub-thread-140.html#post58790176

And the thread for the paint mix:
https://www.avsforum.com/forum/110-diy-screen-section/1311989-official-silver-fire-v-2-thread.html

Thanks, noob00224

I fear you may be right about the 105%, but given how non-existent the actual vendor documentation about this is, and how even some of conflicting information exists about it (e.g.: the way i read projectorcentral throw calculator results about this), i think i will run the exercise of getting the UHD380x and testing it out myself - from amazon, so i can easily return it if you're right. But also get the TW7000 (not quite sure i really need the TW7100 given how in a lit room the contrast isn't going to be ideal anyhow).

I get your point that the non-AVR low-gain screen will not give me as much light rejection vs. less light-reduction for the projectors own light as an AVR screen. Will read through the URLs you provided

How about ALR screens like XY screens "Black Crystal". That looks not only like 0.8 gain, but also like more ambient light rejection, given all the layers these screens have. Is that the superset of no-hotspots but better than 0.8 ambient light rejection ?

https://www.xyscreen.com/standard-throw-ambient-light-rejecting-fabric-black-crystal