Ideal Screen Size for Theater? 2.35:1 or 16:9?

Pretty much all television shows and sporting events are broadcast in 16:9 format, as well as most movies. There are only a small number of movies done in 2.35:1 format, so I would go with 16:9 to support the most media.

If you are able to completely black out your window and make a "dark room", the white screens are the best. The grey/black screens (such as Greyhawk or Firehawk) are for rooms with lots of ambient light. The downside of grey screens are a lower gain and/or have a narrow viewing angle (i.e. people towards the far left or right side of the room will have a drop off in light intensity). Grey screens are 1.1 gain or less and usually require a very hi power (bright) projector for effective light. White screens can have up to 1.5 gain and will have more uniform color balance across the entire screen. Here’s a good reference for screen material types:

http://www.stewartfilmscreen.com/screen-materials/flexible-front-projection

As far as brand, Stewart Filmscreen has been said to be the best, but it is also typically the most expensive. I know that many others have had much success with Da-Lite and Draper screens. I use the Studiotek 130 from Stewart Filmscreen (which is very nice).

Draper has their Pearl White CH1900E screen with a 1.9 gain, but it has a very narrow viewing angle, which is fine if you’re sitting in the middle set area (half gain is reached at only 23 degrees off axis). My Studiotek 130 has half gain at 80 degrees off axis.

I don’t use an acoustically transparent (AT) or perforated screen, but I have read that there’s a 5% reduction/degradation in light with these screens (may be too small for you to care). They are good if you have the room behind the screen to place the speakers and want the speaker location perception to be perfect.  Also, they are not good if you have a very close viewing distance (i.e. 8 feet or less distance from the screen).

Another point. If you are sitting 15 feet away from the screen, it is recommended that the screen size be about 10 feet wide (a good size would be 120" wide by 67.5" high for a 16:9 screen). This gives you the recommended 36 degree viewing angle for the actual movie screen. See this page:

http://myhometheater.homestead.com/viewingdistancecalculator.html

If you used a full 16 foot wide screen, the recommended viewing distance would be 24-1/2 feet away - referenced as "Recommended THX Viewing Distance (36 degree viewing angle)".

I don't think the grey/black are superior to white in general.  They have more resistance to ambient light.  The grey screens are designed to reflect light that is directed straight at the screen (i.e. straight line from the projector), but do not reflect light coming from the sides (i.e. reflections off the side walls).  So, if you are concerned about ambient light, choose the grey.

In your situation, with some concerns about ambient light, I would go with the Greyhawk from Stewart Filmscreen.  It has a very wide viewing angle (almost as wide as my Studiotek 130), but less gain.  The Stewart Greyhawk is more expensive, but it has 12% more gain than the grey screens from Draper and Da-Lite.  When using grey screens, I would try to squeeze out as much light output as possible.

I use a Sony VW95ES (which, in my opinion, was the last excellent 1080p projector Sony made) that outputs 1000 lumens.  I have a 7-2/3 foot wide screen (92") in a completely dark room and the 1000 lumens is just enough to give good light output once calibration from Lumagen Radiance is completed.  In you room, I would recommend at least 2000 lumens (or as much as you could get) because of the larger screen and lower gain Greyhawk.  A 10-11 foot screen is really huge for a common project, plus the lower gain screen means you really need a lot of lumens!  What's your projector budget?

I remember reading about usage of different paints about 5-6 years ago.  I think it was over on AVSForum.  I never did any experimentation with paints.  You might not have the amount of gain that a specific screen material would have (I don't know).  Also, you would have to make sure you used a perfectly flat surface.  Many residential houses nowadays have textured walls.

One thing to keep in mind is that you really need to have a border or some way to black out the entire area surrounding the screen.  There is much light that would reflect off the front wall, event though the projector is primarily aimed at the screen.

I did some calculations. My screen is 52" X 92", which equals 33.2 square feet of screen area. In a completely dark room, my 1000 lumens projector is just enough for my 1.3 gain screen after calibration (calibration will actually reduce some light output because projectors typically push the blue to make it brighter).

If you put up a 11 foot wide screen, it’s going to be 68 square feet (11 x 6.1875), which is twice as much area. With the reduced 0.9 gain of the Greyhawk, you will actually need a very bright projector, something towards 3000 lumens. This could limit your choice of projector (as many choices are only 2000 lumens) or push your cost a lot higher.

Reducing the screen down to 9 feet wide (108" x 61-3/4") would reduce the area to 45.5 square feet. Move your seating to about 13-14 feet away. This option would allow you keep the 2000 lumen projectors as options.

@herman - is your screen 120" diagonal? or 120" wide?  If it's 120" diagonal, the actual width is only 105" (8-3/4 feet).

Also, I specifically stated that mgould would need a much higher lumens if he was going to do a calibration (i.e. grayscale and color cube calibration using Lumagen Radiance -- which is highly recommended anyways).  The calibration will reduce the max amount of light the projector can output.  So, in essence, calibrating a 1000 lumens projector will essentially reduce it to something like 700 lumens (approximation).

In my room, if I don't do a grayscale/color calibration, I can certainly run my Sony 1000 lumens in "low light mode" and the brightness is just fine.  However, when calibrated, I have to use the "high light mode" because there just isn't enough output in low light mode -- the picture is just washed out and there's no "pop" in the color.