Screens with a "high gain" act like a mirror. They limit the range over which you can view the image, and not feel like you are looking into a mirror.
It is important to realize that under 1.5 gain is considered 'minimal' gain, not high gain. Generally 2.0 starts to push things quite a bit and you really shouldn't be using it, but there has been a lot of praise for the high power screen from DaLite in home theater use.
Selecting the Right Screen
But, it is correct that high gain screens should not be used if possible as they are an indication of a very poor environment.
Minimal gain screens, on the other hand, offer a nice mix of added 'pop' to the image without adding hotspotting or visible brightness shift across the image.
The best surface is a clean flat matt white surface. This ensures you get the widest range of viewing angles, and no "bright spots".
This is true if the surface is completely flat and that you have a need for a very wide viewing angle. In reality, the best surface is the one that is best for the specific room and viewing conditions of the specific theater it is to be placed in. For some peopel this may be a high gain screen due to poor conditions, for others it may be a black screen due to uncontrolled light.
Without going to a more expensive screen material (and screen) like a DaLite high contrast cinema vision material, the typical screens are .8 (gray), 1.0 (neutral), or 1.3 (minimal gain). All three look extremely similar, but for 90%+ of all theater installations, the minimal gain screen is the way to go.
After you have your projector, and you've tried it without buying an expensive screen, then start researching the purchase of a screen, if you really feel you need it. You probably won't need it or want it.
The big headache is that a wall isn't a flat screen. It generally can't handle being washed, it also tends to have significant imperfections that become visible when you shine a projector on it and the image pans across the scene. So, it can take hours of work to get a wall completely flat (put a straight edge on your wall to see how truly flat it is). Then, once painted, without roller marks or any blemishes, it does work very well. In fact, do-it-yourself screens can look excellent and don't need to cost a lot of money. But, they aren't 'quick and excellent' - they take time, and it could take a lot of time to get the screen right.
The other problem with a screen, is getting the image from the projector to line up exactly with the black borders of your screen.
This, I am sorry, is laughable.
Not that it isn't tricky to do this, but there is a very specific reason to do this properly and to use those borders exactly as they are.
A 16:9 screen is perfectly rectangular. It has straight edges parallel with each other and is the proper shape and aspect ratio. If you aren't filling it properly, then it means that you aren't seeing a properly squared up image on the screen. If one side is to large, it means that one side is to large! During pans or people walking across the screen, they will get 'smaller' as they go from one side to the other.
It may take 30 minutes to align a good projector (like the 5020/8000) it may take longer if you are a new projector owner, but once it is setup, it will fit perfectly.
If you just use a painted white wall, you can paint black borders on it later, if you want to, and you can paint the borders to match the edges of the projected image.
No - as described above, this justifies not having a proper image instead of having a properly squared up image. As well, paint is not a velvet border which properly drowns out a bit of overspill. A good screen with velvet borders can handle you being off by half an inch and will still look awesome.
This is the difference between a painted border and a true velvet border:
That said, you can certainly make a border out of velvet if you want. I've done it by wrapping base boards with velvet. It looks excellent.
Have a look at the forums.whirlpool.net.au forum and search for post 1286639
Proper link:
http://forums.whirlpool.net.au/archive/1286639
If you are ever serious about painting a screen, check the AVS Forums for the DiY screen section. I generally am not a fan of that site, but their DiY screen section is awesome.
Now, don't get me wrong, I've built a screen myself (blackout cloth), and I've seen painted screens. They can look awesome and they do work very well. But, you have to put the time into it to make it happen and that time could be (and should be) significant to get the best results. As well, you have to live with the reality that they aren't going to be electric. They aren't likely to be easy to break down if you need to move. They can't just have fabric replaced easily if they get damaged, etc. You have limitations that aren't always in place with pre-fab screens.
I know this post reads as very negative to DiY, but after carefully building a screen for hours on my own and hearing horror stories from others who worked for hours to not be thrilled, it is just meant as a cautionary piece of advice.
For first time screen buying I strongly suggest projecting onto a white wall to ensure that you are happy with the size prior to purchase of any screen. Some people like a lot larger than they originally expected while others want something a bit smaller than that.
