The following details are guidelines from several Manufacturers.
If you are unsure which type of Screen Surface to choose, you should ask the Manufacturer of your projector which screen surface suits your projector model best.
The ratio between the width and the height of the viewing area. The three most common aspect ratios are 1:1 (Square), 4:3 (TV), 16:9 (Widescreen) and another is 5:4 (Presentations)
Acoustically Transparent or Perforated
Either a woven fabric or a diffusion surface with tiny holes across the whole area that allows loudspeakers to be hidden behind. This enhances the cinema experience with the voice eminating from where the image is viewed.
Rigid Rear Projection screens can have a Freznel/Lenticular optical lens structures precision cast into the acylic during manufacture. The benefit of this optical lens design is to focus the projected light across the whole screen surface in a uniform manner greatly enhancing the percieved visual display.
Holographic transparent screen that provides an etheral visual display where the rear projected image apparently hangs in mid air. Can be supplied as a rigid acrylic or adhesive film. Projection angle setup is critical. Acrylic version can be flown.
Designed for projection where the projector is placed behind the screen, sometimes in conjunction with first surface mirror rigs. The surface uses a translucent flexible screen fabric or rigid acrylic screen to display the projected image. This fabric or acrylic can be used in rooms with high ambient light conditions. Screen Expert offers a wide variety of rear projection screens with diffusion, freznel, lenticular optical solutions available.
Screen that comes with a remote so that it can be rolled up and down from any location within the room. Typically screens come with an Radio Frequency or an Infra Red remote control to operate the screen. Radio Frequency can operate up to 20m maximum with a 180 degree cone and Infra Red can operate up to 12m maximium with a 60 degree operating cone.
A screen type that comes with a rocker type wall switch so that it can be rolled up and down on operation of the switch. Usually surface mounted with positions for Up, Down and Stop. Usual wiring is 3 core electrical cable to the switch and 4 core electrical cable from switch to the screen.
All our electric screens have a motor in roller assembly to ensure that the surface position is a close to central as possible in relation to the cassette or case.Wiring on the screen is either via 4 core electrical cable or with a terminal block accessable from end cap of screen through removable cover panel. Most of our screen manufacturers use the Somfy leading high quality brand of motor in their products.
Either printed or spray painted black borders that frame the viewing area and create the aspect ratio. The addition of borders enhances the percieved visual display.
Cassette or Case
A screen cassette or case is the housing which a manual or electric screen retracts into. Usually made from folded steel or an aluminium extrusion and finished with White powder coating. Integral fixing points or channels to fit fixings into are part of the cassette or case structure.
Designed to protect portable screens during transport usually made from a durable vinyl material with handles. Fastfold type screens have a sturdy rigid plastic case with both pulling handles, wheels and locking straps.
Specific screens where the body of the screen case is hidden in the ceiling void leaving the ceiling with just a trim flange showing. Some models leave a permanent slit for the surface to drop through and some have ceiling closure. Ceiling recessed screens provide an aesthetically pleasing solution for any installation.
On ceiling recessed screens some models have ceiling closure which completely conceals the opening where the screen surface drops down through. Once the screen is rolled up the closure follows behind to leave the ceiling finished again. Some models are operated by separate motor and some with a hook and latch system.
Electric or manual pull down screens that can be either fixed directly to the wall or can be suspended from the ceiling using either bracketry supplied or supplied by others. Suspending from the ceiling requires careful installation to ensure that a solid fix is achieved.See Fixings.
Ceiling Trim Kit
On certain screen models a trim kit that fixes to the screen case can utilise a specific standard screen like the Draper Targa as a ceiling recessed screen.
Strong steel bracket finished in white that allows the screen to be installed away from the wall. If you require your screen installation to roll down in front of a mirror for example but fixed to the wall, extension brackets provide the solution for the smaller sized screens. Most common sizes of extension brackets are 150mm and 300mm fixed brackets.
“Flying” a Screen
Screens like a Frame Screen or Rigid Rear Projection can be “Flown” by attaching steel cable(supplied by others) to the screen and fixing to the ceiling giving the effect of hanging in mid-air.
Usually supplied by others fixings are the physical screws, bolts, rawlpugs to suit the installation wall or ceiling requirements. Fixings suitable for the application to adhere to Health and Safety regulations and installed using best practice. All projection screens need to be installed level to operate correctly. Failure to do so will compromise the surface flatness.
Gain is a measurement of the reflectivity of any screen or projection surface. The gain number represents the ratio of the light that is reflected from the screen as compared to the light reflected from a standard white surface. A screen with a gain of 1.0 will reflect the same amount of light as that from a white board. Higher gain levels are not always necessarily better for all situations. For example, with a high gain screen the viewing angle is decreased. This means the image will not appear uniformly bright from angles outside the viewing area (image will appear brighter in the centre of the screen). Also hotspotting can occur with high gain screens, meaning certain areas of the screen appear brighter than others. High gain screens are best used in environments where ambient light is an issue and projector positioning is condusive to benefitting from a high gain surface. Some high gain surfaces reflect the maximium gain back towards the projector, so ceiling mounting may be a issue.
A certain area of the screen“spot”appears brighter than its immediate surrounding area.“Hotspotting”is usually only a problem with high gain screens or surfaces with a gloss or partial gloss finish.
Where and electric screen is part of a combination of audio visual products that are ‘integrated’ together and controlled with a single system such as a Crestron or AMX. For example dimming the lights, switching on the projetor, selecting a source and dropping the screen all from a single wall touch panel or hand held touch panel.
Infra Red Kit to control any electric screen ( not including Plug and Play type screens). Consisting of a receiever,sensor and transmitter, IR Kit’s can be retro fitted or installed at the same time as the screen. Operating up to 12m maximium with a 60 degree operating cone.
Radio Frequency Kit to control any electric screen (not including Plug and Play type screens ). Consisting of a receiver and transmitter, RF Kit’s can be retro fitted or installed at the same time as the screen. Radio Frequency can operate up to 20m maximum with a 180 degree cone.
If the projector has a 12v specific trigger outlet then an electric screen can be rolled down when the projector is turned on and rolled up when turned off using a separate Projector Trigger interface. When the projector is powered up an electrical pulse is sent to the Trigger which then sends a pulse to the screen to roll it down and vice versa.
When the screen is rolled down an electrical pulse activates the motor until the roller reaches the limit switch which then switches off the power to leave the screen in the correct position. On rolling up the surface another limit switch operates in the same manner to stop the surface rolling up into the case. The Up and the Down Limit Switch’s as these are known are factory set but can be carefully adjusted if required. See manufacturers installation instructions for details
The ratio between the smallest and largest width image a lens can project from a fixed distance.Most projector manufacturers give details on the specifications relevent to the particular model required to facilitate the minumum and maximum screen width achievable at a given Throw Distance.
Low Voltage Control
Where an 220volt electric screen is to be integrated into a control sytem, the requirement to convert to low voltage (12V) to work safely is needed. Low voltage control modules are available to facilitate this requirement on application.
Electric screens that have the added benefit of a independent masking system( black borders) that allows multiple aspect ratios on the same screen, the ultimate cinematic experience. Can be wall mounted or ceiling recessed.
A screen that can easily be moved from one location to another and is easily set up for projection.
A screen type that is manually retracted from a screen cassette usually fixed directly to either the wall or suspended from the ceiling. Spring roller technology ensures that the surface rolls back into the case and locks into place when pulled down.
Pull Up Screen
Portable screens usually positioned on the floor or table where the projection surface is manually pulled upwards and locked into place.
Portable pull up screen on a single steel column with foldable three leg construction
Plug and Play
Electric screens that are pre wired and fitted with a plug. Control is via either a Infra Red or Radio Frequency system that is built into the motor in the screen.
Either a steel or aluminium tube where the screen fabric is fixed onto. Has a spigot inserted at one end that fits into a bush in the end cap and either a spring roller assembly for manual screens or the electric motor assembly at the other.
Plated steel rod that is shaped into an ‘S’ shape. Can be used to suspend a small screen from the ceiling with either threaded eye or ‘L’ shaped steel brackets ( all supplied by others)
Self-supporting screens feature a heavy weighted base which in turn keeps the screen surface flat. The flatter the screen surface the higher the image clarity. Self-supporting screens are most common compared to Tab-tensioned screens
Spring Roller Assembly
Tensioned spring technology built into the screen roller that facilitates the consistant rolling up and down of the screen surface. Locking system ensures that the screen will stay down for viewing but when released will allow rolling up.
Tab-Tensioned screens feature tensioned cords on both sides of the screen to keep it flat. Many also incorporate a weighted base for extra screen tension. Typically a viewer can see the tensioned cords on the sides of the screen.
Where the flexible projection fabric is under permanent tension by being stretched across a frame. Frame screens and Portable Fastfold are types of tensioned screens. Surface flatness is greatly enhanced by this design.
Throw distance is the distance between the lens of the projector and the screen surface. It is an important consideration when permanently installing a projector. If you don’t know your throw distance please use the screen expert’s throw distance calculator here (hyperlink)
Velcro or Domes
Velcro or Domes (Press studs) are used during assembly of Frame Screens or Portable Fastfold type screens to fix the fabric to the frame and create the tension required for a flat viewing surface
The viewing angle of a screen is the angle you can sit at and still see what is on the screen. Typically the higher the gain value of the screen, the lower viewing angle. Angles used in this catalogue are measured left/right.
The actual section of the screen surface that the projected image is shown and appertains to the aspect ratio of the screen. Black borders on the sides, above and below enhance the perceived visual image.
Black velvet material that is added to the frame on Frame screens to enhance the perceived visual display by absorbing the projected light overspill.