What is a Projection Screen?
A Projection screen is basically a blank canvas that can be coupled with a digital projector to display an image proper for the dedicated viewing space. Projection screens come in various sizes, materials, formats and sizes.
How do they work?
Most projection screens come in one of two types. Front projection screens reflect light back towards the source (projector). Rear projection screens diffuse light through the surface out towards the audience of the other side. For the best results, you want a screen that is free from staining or discoloration and is uniform in reflectivity.
Style: Portable, Electric, Manuel, or Fixed
If your projection application is permanent, then hanging wall and ceiling screens is usually your best choice. However, if you need to move the screen to different locations, a portable screen is a better choice. If you are on a budget, a manual screen will
Portable screens are able to move from location to location readily. Here are a variety of portable screens that you can choose from to best fit your needs.
Floor mounted screens- available in manual and electric models. The manual screen is stored in the base, and extends upwards using a number of different possible manual mechanisms. The electric screens are also stored in the base, but extend upwards using a spring system.
Folding or Frame screens- are supported on both sides by vertical T-legs. They are usually break down into a polyethylene case for storage and transport abd require on to two people for set up.
Inflatable screens- are an innovative new design perfect for the outdoors. Easily assembled and stored.
Tripod screens- are supported by a tripod base and are extremely mobile and easily stored.
Ultra-portable- are smaller formats and are ideal for table-top presentations.
Electric screens are high-end projection screens that add elegance to their mounted location. Electric screens can be tensioned so that they have the smoothest possible image surface. These screens descend and ascend back into the casing with the flick of a switch or via remote control. Electric screens may be externally mounted to the ceiling, or recessed into the ceiling (additional construction may be required). They may also be mounted to the wall, both the wall and ceiling, or ascend up from the floor.
Manual screens are an economical choice for projector screens that stay in one location all or most of the time. The most common application is in the classroom or small office location. These screens are raised and lowered by hand, sometimes using a pull string or rod to reach screens mounted in high locations. They are available in ceiling, recessed-ceiling, wall,and floor mounted models.
A fixed or “permanent wall” screen consists of a vinyl screen surface that is stretched and attached to an assembled frame Most fixed screens have the same viewing surface options. The price is usually driven by the style and look of the frame that surrounds and supports the screen surface. Fixed screens are most often used in Home Theater applications as well as conference rooms due to their elegant look and perfectly flat viewing surface.
Mounting: Wall, Ceiling or Both
Wall mounted screens are easily affixed to your wall using provided or optional brackets. Many may be placed flush to the wall, or extended out a bit to allow for some space behind the screen to accommodate things such as a chalkboard, whiteboard, fireplace etc. Wall mounted screens may be manual, electric, or fixed.
Ceiling mounted screens are easily affixed to your ceiling using a bracket system or hooks. A second option of recessed (hidden) installation is available for some models. Both manual and electric screens provide models perfect for this method of installation.
Some screens may be affixed to either the ceiling or the wall depending on your needs. These screens typically use “L-shaped” brackets that allow them to be flush mounted to the ceiling or wall. This option is available in electric and manual screens.
Screen format refers to the aspect ratio, or the proportion of the width to the height of a particular screen. There are several types of standard formats, and you should choose the format based on the (native) format of the projector you use as well as the types of material you will display the most. Some common aspect ratios are HDTV 16:9, NTSC Video 4:3, Slide 1.25:1, and Square Format 1:1(popular for overhead slide projectors).
16:9- 16:9 (generally named as: “Sixteen-Nine”, “Sixteen-by-Nine” or “Sixteen-to-Nine”) is the international standard format of HDTV as used in Australia, Canada, Japan, South Korea, and the United States, as well as in Europe on HDTV and non-HD widescreen television (EDTV) PALplus.
4:3- Originated in 35 mm silent film, commonly known in TV and video as 4:3. It is also the standard ratio for MPEG-2 video compression. This is the used format for standard definition television screens and NTSC computer monitors. This format is slowly being phased out in favor of widescreen and HDTV formats.
1.25:1- These screens are ideal for slide presentations.
1.1- This is a square screen which may be partially descended to change the aspect ratio. In this case, it could be useful for more widescreen applications, but are ideal for presentations and use with overhead projectors.
Two other formats are the multi-format and the widescreen/cinemascope screens. The multi-format can be adjusted using masking devises. These are multi-purpose, easily adaptable for presentations or video viewing. The widescreen/cinemascope format is used for most movie theater screens.
Masking borders can be added (and potentially removed) as a way to eliminate the bars you see on the top and bottom of the screen when using your projector in its non-native format (ie 4:3 projector displaying in 16:9). They also increase the perceived brightness of an image on a projector screen to give it a top-notch look. The human eye perceives the image to have more contrast, a sharper picture, and brighter colors when masking borders are used.
The highlight of the two-piece projection system is the ability to create a large screen size. When choosing your screen size it is important to note that while it is true that size counts when it comes to home theater, it can be overdone to the point where it is not enjoyable. In a commercial setting size becomes less important for the “wow” factor and more important for efficiency of delivery to the audience. A good rule of thumb is dividing the distance of your furthest viewer by 8 to get your recommended screen height.
Commercial and Educational Applications
Screen height should be approximately equal to 1/8 the distance from the screen to the last row of seats. This is so that text can be read and the details of the presentation can be seen clearly. Ideally, the first row of seats should be approximately two screen heights away. The bottom of the screen should be a minimum of 4 feet above the audience floor. This allows those seated toward the rear of the audience to see the entire screen.
Home Theater Applications
In home theater settings a good rule of thumb is to place your seating at a distance that is equal to 1.5 x the screen width for 720p projectors. With 1080 resolution projectors the rule can be modified to 1.2. The bottom of the screen should be a minimum of 2 feet above the audience floor. This may require additional screen “drop” for ceiling hung screens.
To maximize the quality of the image you are projecting, an important factor is screen fabric. The two most important qualities of a specific fabric are its gain and viewing angle. Gain is the measurement of reflected light on a screen. The viewing angle is the maximum angle at which a display can be viewed with acceptable visual performance. Usually, the higher the gain, the narrower the viewing angle of the surface.
Be sure to choose the screen surface that best suits your projection and viewing requirements. Your choice will largely depend on your projector, seating arrangements, and how much you can control the ambient light in the room. There are several types of screen surfaces with different attributes designed to accentuate the projected image. But, for the majority of users matte white or high contrast matte white will be the two surfaces from which they choose. Matte white screens are the most popular because they provide the most accurate color representation and largest viewing angles. High contrast screens are popular when used in home theaters because the material increases overall contrast by dimming the image.
Most screens will have the matte white type surface. It has a normal gain and has a wide viewing angle. It provides true color representation, so it will better suit your business needs. Many home theater applications are now choosing Matte White due to the quality and high contrast ratio available with the latest projectors.
There are no real negatives to choosing a Matte White surface. The only reason to choose something other than Matte White would be if you need to make some adjustments to your image like added reflectivity or higher contrast.
High Contrast Matte White
Gray surfaces add to the images perceived contrast, making blacks and shadows more detailed.
Gray screens typically has a lower gain and tighter viewing angle than a Matte White surface.
Regardless of whether your screen is for a home theater, office or organization, the price is always a very important factor. For many, the price is the single most important factor in choosing a screen. Screen prices will vary depending on the intended application. But, generally screens start at a few hundred dollars and can go up into the thousands, depending on size, material, and other factors. Some small portable screens have been known to retail for less than $100, whereas installed manual screens start in the $120 range. Electric and permanent wall mounts generally start between $400-$500. For larger formats and extra features you can attain one of the more popular electric or permanent wall mount models between $700-$1200.
When choosing a projector for a home theater, you need to consider what will meet your needs. Are you going to be using your home theater projector to watch regular TV programming and standard DVD’s or are you looking for a projector to connect to your next generation game system, Blu-ray player and HD source box (cable, satellite, etc.)?
The aspect ratio is the number of units wide by the number of units high. The most common aspect ratios for projectors are 4:3 and 16:9. The standard (NTSC) 4:3 ratio image is almost square like a television or computer monitor, whereas the widescreen (HDTV) 16:9 ratio panoramic like a movie screen. Currently the majority of specified home theater projectors have a native 16:9 aspect ratio.
The resolution of your projector combined with the source of the image will determine how sharp your picture is. The higher the resolution of the projector, the more pixels the image has. As your pixel count increases, they can become smaller thus creating greater detail and smaller separation between them. When it comes to home theater projectors there are currently 2 16:9 resolutions 1280×720 and 1920×1080.
The 1280×720 format is a good choice if you have a budget under $1500. 1280×720 projectors deliver beautiful high definition images from HDTV 720p, 1080i, as well as Blu-ray disc players. So there really is not much of a compromise in picture quality by going with 1280×720 instead of the higher resolution 1920×1080 format
The 1920×1080 format has come down in price within the last year+ and a good (1080p) unit can be had for just over $2000. If you want the absolute sharpest and most detailed picture possible from high definition sources, then 1920×1080 projectors are the best choice. While the 1280×720 projectors can deliver very impressive HD images, the picture quality in terms of image detail is even better when the projector has the ability to show all 1080 lines of the signal in their native, uncompressed format.
A projector’s brightness is measured in ANSI lumens. When it comes to home theater projectors, brighter is not always better. You need to have a projector that produces enough brightness for a bright vibrant image, but not too much because additional brightness will wash out the color and contrast. For home theater projectors, brightness typically ranges from 700-2000 ANSI lumens. The amount of ambient light in your viewing environment will be the biggest factor in determining how bright your projector needs to be. Dedicated home theaters with controlled lighting and no ambient light will not require as much brightness as a family room with ambient light from windows or other household lighting.
For home theater projectors, contrast is a very important quality especially when watching movies. Contrast gives depth and shadow detail to video images. Excellent contrast can take a two-dimensional image and make it appear almost three-dimensional. A high contrast projector produces good shadow definition, deep color saturation, and a picture with a rich dynamic look.
There are three installation options for a home theater projector: Table mount, rear shelf mount and ceiling mount. The most common option is ceiling mounting. When ceiling mounting a projector it will only have to be adjusted once during the initial setup. Due to the high placement, heat from the projector is dispersed over the viewers head and the noise level is lower. Also, because of the variety of mounts and colors and because cables can be run inside the wall, a projector can be integrated rather seamlessly when installed on the ceiling. The other options of tabletop and rear shelf mounting are often used for a portable setup or when ceiling mounting is not possible. Both options allow for easy access to the projector; however users may run into the predicament of having to avoid the wiring from the projector.
Remember that a high quality screen is a long term investment. Projectors continue to get better and cheaper with time, but screens are different. It is not uncommon for a person to change projectors every 3-4 years but keep the same screen throughout. In dedicated home theaters, permanently mounted screens make the most sense, because the combine best quality of image with reasonable pricing. The manual or electric retractable screens can be mounted to the wall, ceiling, or can be ceiling recessed. When a dedicated home theater room is not an option and a multipurpose room, like a family room will be used. A retractable screen can easily be concealed when not in use which is a definite bonus. The manual version is less expensive and less glamorous than the motorized version which can be controlled with the touch of a button. The electric screens definitely make an impression in your home theater.
If your projector is going to replace your current television, lamp replacement cost should be factored into your purchase. Lamps typically last between 2000-4000 hours keeping in mind that regular filter cleaning and proper operation will improve lamp life. The average projector used for movies and special events runs 8 hours a week. At this rate, a lamp will last approximately 4.8 years. As a high pressure lamp is used, its light output diminishes. So, many users choose to replace their lamps more frequently than the maximum life in order to maintain a brighter picture. Replacement lamps usually run between $200-$400. If your projector will be used primarily for watching movies and special events, lamp life will not be quite as important. Still, it is wise to factor in the cost of replacement lamps before you decide which projector to purchase. You may also want to purchase a spare lamp when you purchase your projector. This will minimize downtime of your projector when your lamp needs replacement.