At the LCD Projector Center we concentrate very much on LCD projectors, so why am I writing about projector screens? Quite simple really. Buying your lcd projector in isolation from the screen without considering how they work together is likely to cost you more and give you less than perfect results.
How can picking the right projector screen save you money?
One of the biggest challenges when choosing an lcd projector is getting the right brightness for the room you are going to be using it in. For home use you can usually darken the room. This means you can buy a cheap lcd projector, often saving many hundreds, if not thousands, of dollars.
But often darkening the room significantly is neither possible nor desirable. Buying a higher specification projector will give you a brighter image, but it's probably cheaper to buy a high gain projector screen. The quality lcd projector may cost you a thousand dollars more than a dimmer model, whilst quality projector screens that enhance the image brightness and clarity are only a few hundred dollars more.
Projector Brightness and Screen Gain
The brightness of an lcd projector is given in ansi lumens. Typical values for home theater and business presentation use are 500 to 3000. The higher the number, the brighter the picture will be. At the low end a darkened room is essential, whilst at the very top end acceptable results are possible with higher light levels. The current generation of home use projectors are typically in the 1000-1500 range.
The gain of a projector screen is the increase in brightness of the image produced compared to a flat matt white screen. This is given as a simple number, eg 1, 1.5, 2 etc. A gain of 1 means the image is the same brightness as on a flat matt white surface, whereas 2 means the image is twice as bright.
As an example, if you decide you need about 1500 lumen to get an acceptable quality picture, you could buy a projector with that rating and worry about the screen later. Or you could buy a cheaper 1000 lumen model and match it to a projector screen with a gain of 1.5. This would give you an effective image brightness of 1500 lumen at a reduced cost.
Very High Gain Projector Screens
Typical cheap projector screens have gains of between 1 and 1.2. Gains of 1.5 to 1.8 are achieved with high quality perlescent finishes at about double the cost. If money is no object and you need the maximum gain possible then you need a chromatically matched projector screen.
Gains of up to 4 can now be achieved with matched projectors and screens. An lcd projector only transmits 3 narrow wavelengths of light in Red, Green and Blue. A matched projector screen is covered with material that reflects only these wavelengths. Almost all of the ambient light is absorbed or scattered, so the projected image appears very much brighter.
The Downside of High Projector Screen Gain
Whilst projector screen gain might help you use a cheap lcd projector in brighter rooms than it could cope with on its own, there are 3 trade-offs. These are the viewing angle, color shifting and uneven brightness.
High gain projector screens limit the viewing angle. For a screen with a gain of 1 the picture appears high quality out to about 50 degrees from the projector. But at a gain of 1.5 that viewing angle is reduced to about 35 degrees. Over 2 and the viewing angle is down to around 25 degrees, making it much more difficult to layout your room.
Color shifting happens due to the surface properties of the higher gain screens. A true white screen will render colors accurately. By trying to manipulate the way light reflects, a high gain screen can cause a shift in some of the colors. This is rarely a reason not to buy, unless you really do need the colors to be spot on.
The biggest impact a high gain projector screen has on image quality is the change is brightness from the center of the screen to the edge. There can be up to 30% difference at gains over 2. This is usually not too much of a problem, but it does become far more noticable the higher the viewing angle.
A little research and a bit of leg work could help you make great savings. Treat the projector screen as an integral part of your system and buy it together with your projector. Visit stores and insist on demonstrations with a variety of lcd projector and screen combinations.
Choosing a good quality, moderate gain (1.4-1.6) projector screen can decrease the cost and increase the performance of your system. A cheap lcd projector can produce a bright, clear image at higher than expected light levels. So whilst your projector screen may cost more, overall you save.