hd70 100" screen white or high gain?

i use my projector mostly in cinema mode and i'm trying to squeeze life out of an old bulb. i can usually get my room very dark, but sometimes lights are in an adjoining room.
all signs seemed to point to a 1.8 gain screen. i'm looking at the elite silverframe powergain.
my only concern is the viewing angle, which i can't figure out how to calculate.
viewers will almost always be sitting on an 8' long couch, 13' from the screen.
will people on the ends of the couch see hotspots? what if i put a chair next to the couch?
thanks in advance, this is a great forum.

[mechman]

Tyler,

Welcome to the Shack!

I've tested the Elite's PowerGain material myself. It has a viewing cone of 120 degrees so anyone sitting on the couch or next to the couch should be fine. And it doesn't hot spot.

Elite Screen Review

[wbassett]

First... Welcome to The Shack!

Okay screens and gain- Gain is a spec used to gage how bright a screen is as compared to a unity gain white screen. It is just one aspect of a screen but often is mistaken as the most important attribute. It is a tool to achieve the needed brightness for a theater setting.

I'm not trying to be negative, but I'd be careful. Not all companies are totally forthcoming when it comes to gain. Some use industry standards for measuring gain, others have their own methods. I do question a 1.8 gain with a 120 degree viewing cone. That seems awful wide for that high of a gain. As a comparison DaLite has a Pearlescent screen with a 1.5 gain and a viewing cone of 80 degrees. That does seem realistic since we know as gain increases viewing cone decreases.

To have a similar type of screen material with a higher gain, that means that the reflectiveness and sheen has to be higher so the viewing would be lower. Gain due to higher sheen also indicates an inscreased chance of hot spotting. That's the laws of light and physics. Unless Elite Screens has a different way of measuring screen gain and viewing cone we have a disparity here.

Most screens 1.8 gain and over also start to get into the retro-reflective type of screen, meaning they reflect light back at the source like a traffic sign. This requires the projector to be mounted low, like on a table. Mounting a projector on the ceiling for a retro-reflective screen not only negates the reason for getting the higher gain, it could even look dimmer and have a poor image as compared to a lower gain angular reflective screen. Whether the Elite Screens PowerGain is retro-reflective or angular reflective I can't say. I couldn't determin that from their web site but it appears that are implying an angular type screen.

What concerns me about the Elite Power Gain screen is I can't seem to find much of any information about the screen on their site. I was looking for some information on viewing cone, or a gain chart and couldn't find anything like if it is angular or retro-reflective... I couldn't find anything on their site. From what I see the average price for a 100" SilverFrame PowerGain screen is around the $400 mark. That's not bad for a commercial screen, but also not cheap when not knowing all the specs. It could be fantastic, or it could be mediocre. Do yourself a favor and make sure to ask lots of questions on this one. Ask yourself this- Would you buy a car without knowing anything about it? Probably not.

Now... I want to be clear on this, I am not bashing Elite Screens. I am just saying I couldn't get a lot of information from their site.

What kind of price are you being quoted?

This is what concerns me

onebigdoor wrote:

...snip i use my projector mostly in cinema mode and i'm trying to squeeze life out of an old bulb. ...snip
all signs seemed to point to a 1.8 gain screen.

I need to know some more information before I can try to assist you. What size screen do you currently have and what brand is it?

My other concern is the comment that you're trying to squeeze life out of an old bulb. The HD70, while not the brightest projector out there, turns in a respectable 15fL of brightness in max setting on a 104" screen (according to company specs). The HD70 with a new bulb (after the breakin period) will produce a screen brightness on a 104" diag screen of max 31fL (which is unrealistic because actual brightness is rarely what the max specs are) to 12.3fL in Cinema mode, and 23fL in Bright mode. Knowing this projector is a bit lower than manufacturer specs the actual image will be less bright than those numbers.

That's a lot to digest I know. The main point is you mentioned an aging bulb. You really don't want to compensate for that by spending money on a screen, you probably should take that money and buy a new bulb.

Again I would need to know your current screen size to be able to make a screen recommendation, but based on a new bulb after it's been broken in, and assuming a 100"-106" diagonal screen size in a dedicated setting with occasional lights on, I would recommend a screen running in either Cinema mode with the brightness calibrated and adjusted for the room setting (meaning brightness would be increased) or run in Bright mode with the contrast and brightness lowered just a bit for the best calibrated image. For that setup which would be be the estimated 15fL of brightness I mentioned earlier, I'd go with a screen between an N8 and N9 shade of gray, meaning a medium to light gray screen.

Notice something though- gain was missing in that discussion. It doesn't mean gain isn't important, just that it is not as important as most people think. You have to take everything into consideration when building a Home Theater. This is what professional installers do, but once we know what they do we can also do the same and fore-go the expense, right?

[wbassett]

I'd agree with mech about the 120 degree viewing cone. That is more in line with Da-Lite's Pearlescent screen, but that is also rated at a lower gain too (1.5 vs 1.8). Always remember, if the gain is accurate and a true reading as gain increases viewing cone decreases. A 1.0 unity gain screen will have a viewing cone of 180 degrees. That is the max. As gain increases the cone decreases.

I would accept a 120 degree viewing cone for a 1.5 gain screen, which is very respectable. So based on that I would expect the Elite PowerGain to actually be a bit lower than their published 1.8 gain specs, which is still a positive gain. We'd need to know how they are doing their tests and what they are using for standards and reference materials in order to really compare things.

I think overall you'll probably be happy with this screen, but again it concerns me about the statement you are trying to squeeze out as much as you can from an aging bulb. Eventually the bulb will blow and you will have to buy one, so why spend the money on a screen and not a new bulb?

[ajaynejr]

Don't forget that the viewing cone should define the viewing area over which the gain appears to be at least half that published. So for a 1.5 gain in the sweet spot (the center) a 120 degree cone should mean that 60 degrees to the side you see the equivalent of a picture from a 0.75 gain screen.

In the case of a retroreflective e.g. beaded screen and a ceiling mounted projector, the "center" line points up at the projector and viewers may well be 20 degrees off axis (below the center line), with a greater angle when sitting off to the side or sitting on the floor, thus the drop off in apparent picture brightness using this kind of screen.