Glass Bead Screen Or Matte White Screen?

[Pleasure_Paulie]

Hi I'm new here, and was hoping you're advice would guide me in the decision of this screen.

Basically I need to purchase a projector screen for an NEC LCD 2100 (VT470) lumens projector which will be mounted on the roof. Its for a hall that is 80 feet long and 33 feet long. So its a fairly long hall. The conditions arent all that super bright, but not very dim, however sometimes we may have some bright lights on the stage where the screen will go.

I'm looking at a 100" screen as thats the biggest that will fit the hall design, and been offered at a good price a glass beaded screen (gain >2.2) and a matte white screen (gain >1.1).

I've been told that glass beaded screens have bright spots, and are retro-reflective, which means they have a very small viewing angle, plus the projector is mounting from the roof. But they look very tempting.

Should I get a glass beaded, or a matte white screen?

ALL HELP IS GREATLY APPRECIATED!!

 

[av-man]

Your projector has a low lumen rating for your application(2100) When I do a church or other large venue I'm in the 4000 range. Glass bead will help you some but your viewing angle will be about 25%. Usually matte white works fine and gives you 45-50% view without losing anything. With your limited lumens maybe you should change you set up to rear projection if your unit has the ability. This will in some situations allow you to get closer to the screen or get better control of lighting. Try dalite for your screen. You'll have to find a dealer near you. If you can't get any help email or PM me and I'll help if I can.

 

[BMXTRIX]

Glass beaded screens reflect light back towards the projector - not like a mirror would bounce the light towards the audience, but would actually have a much higher roll off rate than the 1.1 screen does once you are outside of the viewing cone.

Do NOT use a glass beaded screen unless the projector is at audience level and there is a narrow viewing area for the screen. This is not your case, so glass beaded most definitely is not the way to go.

The matte screen will definitely reflect more light (like a mirror) towards the seating area and will maintain a more uniform image across the entire screen. Better yet - if at all possible - you may want to try rear projection which may be possible if you plan for it. Rear projection is always better for controlling black levels, dealing with light, and just generally providing a better image. This is quite often done in churches and board rooms when ambient light can't be controlled in the room. Much like a rear projector DLP can deal with ambient light much better than a front projection DLP.

 

[Audioholics]

While you do lose 30 degrees viewing angle (total) on Glass-beaded it will greatly deliver more light output for your hall use. Check your required viewing angles. Hot spots are not as big of a deal if you are going after visibility and the lights on stage may hurt you with a ~2000 lumen projector.

 

[Pleasure_Paulie]

I'm considering glass beaded because I don't think the projector is powerful enough for the size of our hall. However, we did use it on a small projector screen and it was fairly visable from the back and our hall is more narrow then wide.

How would i setup a rear projection on my NEC LCD projector?

If matte white is a gain of 1.1. What would a flat white paint finish be on the wall to give me an idea of gain levels.

Would glass beaded mean that when people are standing, they get max gain, but then the image becomes more dim once people sit down. What does the image look like if people are out of the viewing angle?

Thanks guys!

 

[BMXTRIX]

Rear projection simply utilizes a rear projection screen. You would ceiling mount the projector, just as you are currently planning on, but instead of it being in front of the screen, and reflecting off of it, you would mount it BEHIND the screen and it would basically project through it.

You need a rear projection screen - DaLite offers motorized rear projection screens which work well. It may be a lot easier to keep ambient light off the rear of the screen which will increase contrast, and the light shining straight through the rear projection screen is a great way to increase brightness to the audience.

Gain is a measure of how much light is directed back at specific angles to viewers. A plain white wall should disperse light evenly and have fully viewing angle of 180 degrees side to side and top to bottom. There would be no hot spots and no areas that get more light reflected back towards them.

As screens add optical coatings, like beaded glass - it reflects the light back at specific angles towards the audience. Glass beads, in particular, reflect directly back towards the projector, which is a serious issue if the projector is mounted high and the audience is low. The gain of 3.2 (or whatever) is only achieved within a limited angle. As you move towards the edge of that angle, gain falls to 1.0 - then outside of the angle, it will drop below 1.0 and people will receive LESS light then they would with just a plain white wall. 60 degrees off (edge seats, or way under the projector angle) may receive less than half the light the projector is capable of delivering to them.

I am not a fan of glass beads under most circumstances - especially in commercial environments due to the specific angle they reflect light. If you are pointing the projector down, then a NON beaded screen may give you a 2.0 gain, but actually put that 2.0 gain on a path out towards the audience instead of back at the projector which will give more people a better image and won't be nearly as limiting as the beaded screen would be.

Once again - just my 2 cents on the question.