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Discussion Starter · #1 ·
Hi,
I am trying to setup a projector system for my church. We have a stage and I am planing on using the projector to create the backdrop of the stage. I have found a projector, BenQ MP776 ST, and need to mount it 16' from the screen. This has to be the measurement because the ceiling is too high (30') at all other locations. With this throw distance I get the screen size I want (~27' x ~15'), but I still have to mount the projector to get an accurate dimension measurement.

The problem I have with my stage is that it is not always dark and there are times when the stage lights are on. Based on preliminary testing I can see that the backdrop image will be dark enough with the lights off, but needs a higher screen gain (I think) to get a darker image with the lights on. I can not afford a real projector screen and need help with a DIY screen. I want to create a framed projector screen, but do not know what to do.

Here are some of my questions/suggestions:

1. Highest gain DIY screen as possible. I think I will need this to produce an image with the lights on. Please advise me and let me know if this is not the case.

2. It has to be painted? I think this produces the highest gain, but do not know if there are other high gain materials.

3. Screen cannot be too heavy. I am thinking about using sheet rock to produce the screen, but am concerned due to the weight. I could use a blackout cloth, but it is expensive and there would probably be seams. I dont know what the cheapest material to use is for a screen that will probably get painted. Could I use bed sheets since I have those readily available? Please let me know what the cheapest way to create the big screen. Note: I would not mind seams if it meant a cheaper cost of production.

4. Also, Grey vs White?

Please help me figure out how to make the screen.
 

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Am I reading this right? 27 feet wide by 15 feet high?!? :eek:

I'm unsure if there is anything that will give you a decent image at that size.

The best I can figure from PJ calculator is that for a 15 foot tall screen you would have 7fL at the screen. We are actually working, slowly, on a high gain (>3) diy paint mix. And for the life of me I never thought any one would need it. :dontknow: You may be the one who does! :sn: Do you have a Lowes nearby? Can you wait a couple weeks?

Outside of this your best bet is to talk to Elite Screens about their StarBright 7 material. It's intended for uses such as this. They mainly cater to houses of worship and schools with this material.

What's your budget? If money isn't a problem I'd contact Elite about the StarBright. There is nothing out there, diy-wise, yet that would give you enough gain.

One other thing to keep in mind is that gain does have it's pitfalls. If you're looking for an unlimited viewing angle, it's not going to happen with a high gain material. All of the high gain materials that I have seen drop off quite rapidly as you move off center - generally about 30 degrees or less the gain is cut in half.

Welcome to the Shack by the way! :T
 

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After re-reading your post, is it safe to assume color accuracy is not that big of a concern? If it's not, we can get you a paint mixture that will get you the required gain. Keep in mind that it hasn't been tested thoroughly and we're a bit unsure as to what kind of result you will get. You can try it out small at first and if it works do the whole thing. Let me know if you want to give it a shot.

As for what to paint... I'd say BOC. And you will have seams. Maybe find someone good with a sewing machine to sew two pieces together for you. And then you'll have to figure out the frame to staple it to.

Unofficial gain of this diy mix is ~2 (I just did a test of it unofficially).

And the current reading I get from the sample is this:

RGB 152 147 142
xyY 0.323 0.337 29.5
L*a*b* 61.2 1.0 3.21

Ideally you'd want the RGB's to be even, the a and b to be as close to 0 as possible, and the x to be 0.3129 with the y reading 0.329. As you can see it's a bit off and would have a slight red push. We've had this on the back burner for awhile cause we haven't had time to work on it.

This is Bill's (wbassett) baby. I thought it was nuts to have this mix but you've definitely proven me wrong! :rubeyes:

Given a couple weeks, maybe after the new year, we could probably iron this thing out. :nerd:
 

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Welcome to the Shack!

mech already covered things well... just throwing in my 2¢
Hi,
I am trying to setup a projector system for my church. We have a stage and I am planing on using the projector to create the backdrop of the stage. I have found a projector, BenQ MP776 ST, and need to mount it 16' from the screen. This has to be the measurement because the ceiling is too high (30') at all other locations. With this throw distance I get the screen size I want (~27' x ~15'), but I still have to mount the projector to get an accurate dimension measurement.

Now we're talkin! I see people call other projector's 'light cannons' but now we're actually getting there with 3500 ANSI Lumens!

The problem I have with my stage is that it is not always dark and there are times when the stage lights are on. Based on preliminary testing I can see that the backdrop image will be dark enough with the lights off, but needs a higher screen gain (I think) to get a darker image with the lights on. I can not afford a real projector screen and need help with a DIY screen. I want to create a framed projector screen, but do not know what to do.

Here are some of my questions/suggestions:

1. Highest gain DIY screen as possible. I think I will need this to produce an image with the lights on. Please advise me and let me know if this is not the case.

Gain is a tool, but also has issues. Too much gain and you'll actually start to lose your blacks, which is the opposite of what you are trying to achieve.

You mention you still need to mount the projector, will it be ceiling mounted or floor mounted? This will dictate whether you need a retro-reflective screen or angular-reflective screen.

It looks like you'll need something with a gain around 2. We also need to know where the audience will be sitting to determine whether they will be within the viewing cone.

2. It has to be painted? I think this produces the highest gain, but do not know if there are other high gain materials.

No, paint isn't the only way. As Mech mentioned you can go with something like an Elite StarBright 7. As far as DIY, yeah you pretty much are limited to a painted option because there simply aren't any substrates that big! In fact finding a commercial screen that size is going to present a problem too unless you go to a specialty material/order and it's not going to be cheap.

3. Screen cannot be too heavy. I am thinking about using sheet rock to produce the screen, but am concerned due to the weight. I could use a blackout cloth, but it is expensive and there would probably be seams. I dont know what the cheapest material to use is for a screen that will probably get painted. Could I use bed sheets since I have those readily available? Please let me know what the cheapest way to create the big screen. Note: I would not mind seams if it meant a cheaper cost of production.

Sheet rock is going to be very heavy at that size. Check Rose Brand out and call them. Their staff is very helpfull and they even have material in the size you need or they can professionally sew the material for you. They also sell screen material that is used for stage productions and large venues like a house of worship.

Another place to check is your local marina! Look for a canvas shop that makes sails. They will definitely be able to provide material in the size you need.

4. Also, Grey vs White?

What you need is definitely gray and some gain. You're not going to get where you need to be with just a high gain white screen or a plain gray screen. The gray is what is going to save your CR and blacks and keep the image pleasing to the audience.

Please help me figure out how to make the screen.
Here is something you can try too if you are feeling experimental...

Check your local Walmart and look for Gardner-Gibson Black Jack 5160 water based Aluminum paint and paint your canvas/material with that. This really isn't that much different than what Adel Berri did when she made the first Silver Screen. She was dealing with dim projectors back then and had to figure out a way to eek out every bit of brightness that she could.

Black Jack may be hard to find though. You can get aluminum roof paint and try that, but it isn't exactly user friendly nor is it intended for indoor use so I'd be careful on that route.

Or you can try an experimental mix :)
 

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Discussion Starter · #5 · (Edited)
Thanks for the quick responses.
The major purpose of this application is to provide a backdrop for the stage. It is going to be a still image and I do not mind color and quality being slightly less. My main concern is to have the image viewable with the lights on. (The lights are not normal, super bright stage lights, but track lights you find in homes).

Another option i was thinking about was using multiple pink insulation foam and painting it so it would look like a giant projector screen. I estimated out the total cost, minus paint to around $300.

To respond to mechman:
I don't mind waiting, and will probably put it up in January anyway.

It is going to be a ceiling mount

My budget is as cheap as possible, while still getting an image with the lights on.

I have a Home Depot really close, and could probably get to a Lowe's if I needed to get something badly.

To respond to wbassett:
I know there are professional screens, but I need to get this done with a minimum cost becuase I already used my budget for the projector.:D

I was looking online and saw a DIY paint called S-I-L-V-E-R. (I can send you the link if needed)
They say that there is no viewing cone problem and it has a high screen gain. I think the only problem is that they dont have good numbers in ambient light. Is there something similar I can use.

Couple of other things:
Most people are going to be sitting at a maximum of 25° off center of the projector.
Also, what is the cheapest i can get BOC, because I was looking into it and though it was expensive.

Thanks again for all the help.
 

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We know about SILVER :)
They say a lot of things.

SILVER is actually an okay screen option, albiet extremely difficult to apply and is a spray only option. It's pretty close to Designer White, just not as neutral but not bad either. As far as the gain of SILVER, I wouldn't exactly call it a high gain screen. The gain is nowhere near what you need though, and it isn't a screen that performs well with ambient light.
 

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Hi purvz,

Another welcome to ya!

I would forget about using a S-I-L-V-E-R screen for a number of reasons:
  • The gain isn't high enough (about 1.3)
  • There is a viewing cone with the mix and brightness drops fast when viewing off-axis (the gain drops to 1.0 in just 15 degrees). See Mech's Gain Readings here.
  • This paint mix is very hard to apply with any consistency since it depends on seven light layers of paint. The mix also goes on almost clear since it is 95% clear medium and it can be hard to tell where you have sprayed and where you haven't unless you have some spraying experience and have some lights set up at a steep angle to the screen while spraying; and it must be sprayed.

Is there any way you could post some photos of the area the screen will be going, with the lights on as would be normal during screen use? To do so, use a photo hosting service such as Photobucket or Imageshack and then post the links they give you after uploading your photos to them here.
 

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One thing about large venues is the screens usually are large and the audience is usually back a ways.

Viewing cones are always something that needs to be taken into consideration, but the further back the audience is, the wider the rows can be and still be within the viewing cone.

purvz you said this will be more of a background image for a 'stage' setting right? Another option to possibly consider is to rear project the image. That will solve some issues but also creat a few of its own.

mech I say he should be fine with the experimental high gain mix. I'd love it to be tweaked in, but if he's not too worried it should be fine. Besides, that color balance you took isn't really any worse that some of the SF screens we've seen. The one thing we have to check though is what the viewing cone is on that and see if it's greater than a 50 degree cone.
 

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mech I say he should be fine with the experimental high gain mix. I'd love it to be tweaked in, but if he's not too worried it should be fine. Besides, that color balance you took isn't really any worse that some of the SF screens we've seen. The one thing we have to check though is what the viewing cone is on that and see if it's greater than a 50 degree cone.
I'm planning on tweaking it this week. I don't think it will be too difficult to tweak it. The problem may be getting Lowes to match it. But it should end up respectable. It does kind of look like a backwards Silver Fire doesn't it! SF has the blue push this one the red. ;)

I don't have too much going on this week so I should get it done. And I agree on the viewing cone, I'll check it out with a panel. :T

What were we calling this? It's got to be something good seeing as how it may be the first diy paint with a 2.0+ gain. SHoGun was it?
 

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purvz,

Check the viewing angles. How wide of a viewing angle do you need? If you have a perpendicular line going straight out from the center of the screen, what's the farthest angle this will be viewed from (left and right)?
 

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Discussion Starter · #11 · (Edited)
Even if the color is going to be slightly off, I don't think it will be much of a problem for my purposes.
Furthermore, the majority of the viewing angle will be between 0 - 20 degrees, with most of these people being withing 0-15 range. There will be some, the volunteers, that will have a bad viewing angle, but it does not really matter for them.

I thought about rear projection, but could not get the right distance to produce a full image.

Also, I had a couple of questions about my setup:
If I have a high gain screen, do you think I would be able to keep 10-15 incandescent bulbs running, they are the source of our stage light?
Also, if we were to keep the stage dark, do you think there would be a problem regarding the image being too bright?
Would the things from Lowe's also be available at the Home Depot?

Finally, Could you give me feedback on using the foam insulation and how much cheaper/or more expensive it would be compared to the BOC.

I have attached a few pictures to help you out:
I have attached a link to the album to help you get a better idea. Sorry about the pictures being bad, but there are the only ones I have right now.

http://img199.imageshack.us/gal.php?g=dsc0412b.jpg

The first picture shows only the stage (the area that can be seen from off stage)

The second picture shows the majority of the viewing angle of the audience. Also, the distance from the stage and where the people are is approximately 50 feet.

The third picture shows a closeup of the stage (the fill stage). Also, the lights can sort of be seen from the top. In the picture they are all on, but once we get the projector we can decrease the number of lights we use.
 

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Even if the color is going to be slightly off, I don't think it will be much of a problem for my purposes.
Furthermore, the majority of the viewing angle will be between 0 - 20 degrees, with most of these people being withing 0-15 range. There will be some, the volunteers, that will have a bad viewing angle, but it does not really matter for them.
Excellent!

Also, I had a couple of questions about my setup:
If I have a high gain screen, do you think I would be able to keep 10-15 incandescent bulbs running, they are the source of our stage light?
I would think so.

Also, if we were to keep the stage dark, do you think there would be a problem regarding the image being too bright?
Doubtful at the size that we are talking about. But keep in mind this is a experimental mix.

Would the things from Lowe's also be available at the Home Depot?
No. It's only available from Lowes. Do you have one close by? I can check out Home Depot, but I'm fairly certain that they do not have what we would need.

Finally, Could you give me feedback on using the foam insulation and how much cheaper/or more expensive it would be compared to the BOC.
I would think that one big piece of BOC (can be two sewn together) would be cheapest and work best. You could attach grommets in the corners and hang it with bungee cords.

This is a 4:1 mixture using Auto Air Aluminum. You may want to buy 64oz of this wherever you can find it - either locally or from Dick Blick online. I figured your screen will be roughly 400 square feet. That will be two gallons of paint. We'll keep the base a secret for now. ;)

Also, is there anyone from the church who is a professional painter? You may want to employ them to paint the BOC. Spraying normally isn't required but on a screen this size I think it's a must. If you have to do it yourself I would just rent a regular airless paint sprayer. This is way too big of a job for the Wagner Control Spray. Rent a sprayer and practice spraying the BOC with primer.

I'm going to tweak the base some this week to get it a tad bit better.
 

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Discussion Starter · #13 ·
Its great to know that this would work. Also, I found some canvas drop cloth like material that seemed to be nicely finished. It would cost < $100 to make the whole screen. Do you think that it would be a good alternative, because the BOC is over $300.

I can get to a Lowe's its a half hour away, but dont really know what they have.

I also have the ability to paint it we have a sprayer, but I am waiting on the recipe. You dont have to rush, but I will finish the screen and send you the results once I have finished.

Thanks for all the help.
 

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Its great to know that this would work. Also, I found some canvas drop cloth like material that seemed to be nicely finished. It would cost < $100 to make the whole screen. Do you think that it would be a good alternative, because the BOC is over $300.

I can get to a Lowe's its a half hour away, but dont really know what they have.

I also have the ability to paint it we have a sprayer, but I am waiting on the recipe. You dont have to rush, but I will finish the screen and send you the results once I have finished.

Thanks for all the help.
Canvas should work just fine. Prime it first though.

Going back to those lights... They should be fine, but try not to point them directly at the screen. DIY or commercial it won't matter if you have lights shining directly on the screen itself.
 

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mech this will be pretty cool and a great new addition to our growing screen arsenal!

Someone elsewhere is looking for a screen in the N4-N5 range and they were asking about Black Widow. Of course a certain person jumped in and told them BW is trash and doesn't perform well and isn't a dark screen... the typical stuff we always hear.

As far as I know this will be the first legitimate 2.0 gain DIY screen and it's an N6 screen to boot!
 

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It was your brainchild Bill! :clap: I'm just your tweaker. :rofl:

And remember it's 2.1 gain. If we round up like some do that would be what? 3.0? :bigsmile:

I think it would be relatively easy to get it to N4-5 too. Right now it's sitting at an N6.

I also have the ability to paint it we have a sprayer, but I am waiting on the recipe. You dont have to rush, but I will finish the screen and send you the results once I have finished.
I should be able to get it closer by Friday. Expect something then. :T
 

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We're a team :)

I was just saying that this is a major break through no matter what others say lol.
 

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A quick update. I've gotten the mix to a much more acceptable level. I'll get an official reading of it tomorrow after 24+ hours of curing. Earlier today it was around 140 for RGB and it comes in as a N5.5 gray I guess. Gain still appears to be up there - it looks to be as shiny as the original. I should be able to get a sample quart of the proper base mixed up and tested by Friday. :T
 

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Since this really isn't for a screen and doesn't have to meet any standards, I think you can just go with the original formula. Especially since my follow up should have been closer but turned out farther away.

From Lowe's you will need 1 gallon per coat - I suggest two coats - of Valspar Brilliant Metals Pearl base tinted

104 - 3.5
107 - 2.5
116 - 1

Mix this up with Auto Air Aluminum in a 4:1 ratio - 4 parts Valspar to 1 part Auto Air.

I'd recommend spraying a screen your size. You may want to call Lowes ahead of time as I'm certain that they won't have 8 quarts of the Brilliant Metals material on hand. Call ahead and see about special ordering extra.
 
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