Building theater that is 15 x 21 with first row of seat at 11+ feet and second row on riser at about 15 feet. If anyone has their first row at this distance, how big is your screen? I am thinking about somewhere from 96 to 108 wide 16 x 9. Opinions please. Obviously would like a screen as big as possible. Will be using 1080p projector with at least 1250 Lumens but may go higher so that light output will not be an issue. Thanks

Pretty please!

For what it's worth, I have a room very close to your dimensions and I chose a 118" Carada. It's just under 108" wide. It does depend on your projector since you are sitting somewhat close.

I have been doing a good amount of research regarding screen size in relation to distance of viewers. I found this at projector centrals screen guide:

Screen size recommendations from Da-Lite:

* Screen height should be approximately equal to 1/6 the distance from the screen to the last row of seats, allowing text to be read and detail to be seen in the projected image. Ideally, the first row of seats should be approximately two screen heights away.

Elite Screens states that the front viewers should be no closer to the screen that the diagonal measurement of the screen. So a 110" diagonal screen should have viewers no closer than 110"

As mentioned, many sites say the formula depends on the quality of the projector. It only makes sense that a higher quality image will allow you to be closer before imperfections are noticed

I have been doing a good amount of research regarding screen size in relation to distance of viewers. I found this at projector centrals screen guide:

Screen size recommendations from Da-Lite:

* Screen height should be approximately equal to 1/6 the distance from the screen to the last row of seats, allowing text to be read and detail to be seen in the projected image. Ideally, the first row of seats should be approximately two screen heights away.

Elite Screens states that the front viewers should be no closer to the screen that the diagonal measurement of the screen. So a 110" diagonal screen should have viewers no closer than 110"

As mentioned, many sites say the formula depends on the quality of the projector. It only makes sense that a higher quality image will allow you to be closer before imperfections are noticed


The da-lite formula seems way small. If I'm 20 feet away times 1/6 = 3.3'? Way small for my taste. My current height is 52" (106 dia) and I think it could go bigger (if the door weren't in the way).

The da-lite formula seems way small. If I'm 20 feet away times 1/6 = 3.3'? Way small for my taste. My current height is 52" (106 dia) and I think it could go bigger (if the door weren't in the way).

How far is your viewing distance?

Historically there have been several things one could base screen size on, and some of them are becoming less important every day.

From a vision standpoint it boils down to at what point your eyes can discern SDE and how wide a field of vision you and your guests are comfortable with. With the higher resolution projectors SDE is becoming a non-issue for most.

So that leaves field of vision and equipment (projector, screen and room) based on what projector screen combo you have and the ambient light levels in the room and of the room you will have a foot Lambert level you will want to shoot for. Keeping in mind things like bulb dimming etc. its common to plan on running the projector in eco mode in the beginning and saving the higher power setting for later. I went as far as even planning on starting with brightness lowered under the eco setting.

Not only do you have to think about your center seats in each of your two rows but also the side seats. Screen gain in most cases comes at the sacrifice of viewing cone, while ambient light rejection comes at the sacrifice of gain in most cases.

There is then the issue of screen height and height location of the screen. This is highly dependent on the type of seating you pick IMO and if you will be running a center audio channel and where you want to place that. You also have to envision a setup where the people in your second row are not looking at the heads of the people in the front row, (higher riser as in stadium seating or higher screen with slightly different seating angle for the front row as in normal theater)

All that said, there is nothing better than going to your local movie theater (with a tape measure or string) and finding your favorite seat. At arms length straight out measure how wide the screen is in your field of vision. Then move up a few rows till you find your limit and record both numbers. When you get home sit at the distance your seating has to be and have someone put two pieces of tape on the wall repeating the arms straight out measurement.

I personal like to be slightly immersive in my viewing but just short of the image edges being out of my field of vision. Try and keep in mind how small the image was on your CRT TV for years when you sat across the room.

Given the information you provided if it were for me I would suggest a 54x96 16:9 screen. Or possibly a 54 inch high screen in wider cinemascope width, and the option of using the projectors zoom for scoped movies and side curtain masking for 16:9 movies.

Sort of a related question, since the last poster mentioned ftL:

Going from this formula:
ftL=lumens in best mode*gain/sqft of screen/2 for lamp degradation after 200 hrs

For example, using an Epson TW700/810 with a rated lumens in TheaterDark1 mode (eco lamp) = 230
A 102" screen = 1.4 gain & 31sqft

The formula means that my ftL= 6.7

This is way below the recommended 12-16 ftL.

Are my calculations wrong here? How can people be satisfied with the screen with this kind of ftL value?

In Natural mode (an ambient light mode), it still only measures ftL=8.5 on normal lamp and not eco.

Am I missing something here?

Sort of a related question, since the last poster mentioned ftL:

Going from this formula:
ftL=lumens in best mode*gain/sqft of screen/2 for lamp degradation after 200 hrs

For example, using an Epson TW700/810 with a rated lumens in TheaterDark1 mode (eco lamp) = 230
A 102" Carada BW = 1.4 gain & 31sqft

The formula means that my ftL= 6.7

This is way below the recommended 12-16 ftL.

Are my calculations wrong here? How can people be satisfied with the BW with this kind of ftL value?

In Natural mode (an ambient light mode), it still only measures ftL=8.5 on normal lamp and not eco.

Am I missing something here?

FL = (230 * 1.4) / 31 = 10.38 now if you want to divide that in half you would get 5.2

I really think dividing by 2 might be too severe in your case for bulb dimming but basically your math is intact. You may be slightly low on your lumen estimate also but without some testing it’s just a good guess.

I’m assuming you are in a totally light controlled setting and the rest of the room is optimized for max PQ.

IMO you could be down in the 7 to 10 FL range and still be enjoying a nice image. The thing a lot of people don’t take into account is the ability of our eyes to fully dilate and see extremely low light levels. I have posted quite a few times that we should never trust our eyes as light meters because of these variable apertures. Consider sitting in your living room reading the paper with a couple of lights on and you assume its correct amount of light for reading. You then go outside to a sunny spot and continue reading your mind will tell you that it’s maybe twice as bright outside as inside. But if you took a light meter reading you could find out it was more like 10 to 50 times as bright. The difference being our eyes constantly trying to send an image to the brain at a certain brightness. Going the other way into pitch black we will process the low FL from the screen as brighter than the math shows us.

In my case my projector is listed at 2000 lumen and I may be delivering 1000 to the screen of 48 sq ft with a gain of maybe (.7) FL = (1000 * .7) / 48 = 14.6 I don’t know if those numbers are really accurate but like your they are good guesses. Conventional wisdom would say at 14.6 FL I should be just about perfect and under total light control I have a very bright image. And my eyes I’m sure adjust to it and I’m sure its at least twice what would be acceptable. Where it buys me something the low gain screen and the extra lumens is when I chose to view with ambient lighting. Viewing sports etc with a group of people the seating end of my room is about living room bright or slightly less. During this type viewing you could easily read the paper. Below are two screen shots one taken lights out one with (8) 60w flood lights on and several other lights some as close as 3 foot in front of the screen.

Click on the thumbnails to see bigger image or more images

http://thumb2.webshots.net/t/36/36/3/8/31/2125308310068493142TUAWqG_th.jpg (http://entertainment.webshots.com/photo/2125308310068493142TUAWqG)

http://thumb2.webshots.net/t/36/36/4/4/38/2834404380068493142hXjHIr_th.jpg (http://entertainment.webshots.com/photo/2834404380068493142hXjHIr)

This lighting level is extreme but I took the picture to show that a image is still there and viewable under such lighting.

My apologies to the OP if the topic has drifted some. But most of this are issues to consider with your original question.

Thanks bud.

My concern is if I go higher gain than 1.4, and since those higher gains screens are mostly retro-reflective, than I'd be negating the extra gain anyways as I am ceiling mounting.

I'm getting some samples of various gain screens to do some experimenting with before I decide to buy.