Designer White too bright?

[hoju]

Not sure how to proceed on a screen so here I am.

A little background;

We have just purchased a new home and the bedroom in the basement is slated to be a dedicated home theatre. An Infocus IN76 is ready to be picked up tomorrow and I have the day off to start the work.

The room is 13wide by 11 long so the throw for the lens will be 11 feet. This is going be achieved by taking out a part of the back wall and using the closet that backs onto it as a cubby to hold the projector. It basically will be shelf mounted but at the same level as if it was ceiling mounted. Make sense?

The walls will be dark brown as well as the ceiling will be a tad lighter but still quite dark.
I also have total light control to darken the room.
Seating will be right against the rear wall so about 9' or so.

Using the projector calculator and review from projector central I see that the IN76 will be able to project a 100" image from 11' and that is my goal right now, once the projector cubby is ready I will adjust the size more for comfort and then start on the screen.

After reading and reading I have decided that I would like to make a laminate screen but I am not sure if the designer white will have too much gain (I only understand a small portion of gain). I've set the calculator to a throw of 11' but I can't get the green portion of the recommended brightness to the 11' foot range (Adjustable gain goes to 0.8). Will the DW work for me or should I look at another option. Most viewing will be with no light in the room (or a tiny bit as needed/recommended).

Any suggestions on the screen or will DW work? Any other suggestions anyone can make about other things are also welcome.
One last question, but not screen related. I have the AVIA calibration disc from when I bought my 51" RPTV Toshiba, will this work for calibrating a projector also or should I look at another calibration disc?
Thanks;
Mike

[wbassett]

First and foremost, welcome to the Shack!

Based on what I am seeing from the calculator you're going to have around d 41fL of brightness at the screen with that setup and a 1.2 gain screen. That is an insanely bright image and yes, I think you will find that will be way too bright and cause major eye fatigue.

Even with a darker gray, you are going to run into hot spotting issues and I will be honest I don't even think a poly coating will be enough. If you drop down to a .8 gain screen you'll still have 27fL of brightness. You might want to check into some Neutral Density filters to knock down the lumens some more.

There is an added benefit to using ND filters and that is as the bulb ages you can remove the filter/filters and still maintain the same image brightness throughout the entire life of your bulb. Right now that is the direction I would recommend, a darker gray screen that still produces white whites, and then kill the excess lumens with ND filters.

Hit SmokeyJoe up and see if he has any recommendations, he may know of a few things to deal with your situation. We'll get you hooked up though.

[cynical2]

Welcome to the Shack, Mike!

First, I'll take the easy question...yes, your Avia DVD will be fine for calibaration.

Now, onto your screen selection. I have to say, I'm questioning the calculator values on PJ Central.

The PJ will produce a REAL 1000 lumens (not ANSI lumens) in it's more aggressive (brighter) modes. However, if you dig into the details of the review, you find this...

PJ-Central-Review wrote:

Once we set our review sample of the IN76 to deliver optimum video performance, we measured lumen output to be 645 lumens in high lamp mode, and 490 lumens in normal mode. That means it is a very bright unit, and capable of putting out more light than most projectors rated at 1000 lumens.

If we look at a 16:9 100" diagonal screen (gain=1), we'll find that it's 49" x 87.11". This is 4268 sq in, or 29.64 sq ft.

To calculate ft-L, we divide lumens by area (in sq ft).

So, for high lamp mode, we get 645/29.64 = 21.8 ft-L.

In low lamp mode, we get 490/29.64 = 16.5 ft-L.

Keep in mind, these calculations are based on measurements from a brand new projector. The calculator actually appears to be using a full 1000 ft-L (most aggressive, least accurate mode, and a brand new bulb), which is inconsistent with the way I've seen their calculator work for other projectors. In fact we typically find that the PJCentral calculator results are very conservative...so to me the methodology used for your pj seems to be an anomaly in their system.

The net is that with one set of numbers (the ones that make sense, at least to me), a laminate screen seems like a very good fit. But, using the calculated values, it makes it appear that the only way you could use laminate is with an ND filter.

Any thoughts, Bill?

[wbassett]

I agree Jim that does and did seem high.

They are obviously using full out max Lumens in their calculator not what they calibrated for in their review; 1000/29.64 * 1.2 (gain of DW was rated at 1.24)=40.485 fL

I didn't read the review, sorry about that guys. Still it is a very bright projector, probably still too bright for DW unless an ND filter is used, but that's not a bad thing. As I mentioned you'll be able to pretty much go the full life of the bulb with just about the same image brightness throughout it's life. Once you remove the filter, and the bulb ages more and starts to dim, you can kick it up to a higher brightness, but at the expense of eating bulb life faster. I'd say if you go that route, when you finally have to max out your Lumen output you should be looking for another bulb, but it should keep you going better than going for the darkest screen possible and then as the bulb ages your image dims. Once you're used to the brighter image you won't want to sacrifice and probably would be buying a replacement bulb a bit sooner than you planned. Just some food for thought.

I will shoot PC a line though and verify their numbers.

[hoju]

Thanks for the replies guys, I still have no internet access at home so I sneaking in here at work

I picked up the projector last night but didn't have a chance to do anything with it besides fire it up and see the welcome screen. It didn't look too bright the but wall is currently a light beige. Would a safe bet be to try a fashion grey and then see if a filter is needed? To be honest I hate painting so I would prefer to avoid it if I could since I already have to paint the room but if there is another better option (in your opinion of course) I would also consider it.

Thanks again,
Mike

[Scuba Diver]

If you want a sample of DW let me know. I have some left over from my setup.

[hoju]

Scuba Diver wrote:

If you want a sample of DW let me know. I have some left over from my setup.

I'm good, thanks for the offer. I am going to try the platinum and report back to you guys and see how it works out since I can get it relatively cheap. Hopefully I'll have some pics up by the end of the weekend.

On an aside, FJ, do you make it up to Vancouver BC to dive ever? If you are interested let me know, I've heard that you have some nice dive parks also. I have just over 25 dives and am loving it

[Scuba Diver]

hoju wrote:

I'm good, thanks for the offer. I am going to try the platinum and report back to you guys and see how it works out since I can get it relatively cheap. Hopefully I'll have some pics up by the end of the weekend.

On an aside, FJ, do you make it up to Vancouver BC to dive ever? If you are interested let me know, I've heard that you have some nice dive parks also. I have just over 25 dives and am loving it

Yes, I have done some diving up there in the past. It was a fun dive. Lately I have been diving in the northwest mostly to crab and fish. Where have you been? I have dove at several locations in Mexico, California, Hawaii, St. Martian, Singapore, Thailand, Malaysia, Canada, islands I don't remember the names of and Washington of course. Warm water diving is by far my favorite. I have done some Shark dives, night dives, cave dives, wreck dives, fishing, crabbing, and photography. I love it all. I have never had a bad dive. However, I have had some scary dives that I just call new experiences.