Glossary

Aspect Ratio

Is simply the ratio between the width and the height of the viewing area. The four most common aspect ratios are 1:1, 4:3, 16:9 and 5:4.

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 audio emanating from where the image is seen.

Black Borders

Either printed or spray painted black borders that frame the viewing area and create the aspect ratio. The addition of borders enhances the perceived visual display.

Cassette or Case

A screen cassette or case is the housing which a manual or electric screen retracts into. It is 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.

Carry Case

Designed to protect portable screens during transport, and usually made from a durable vinyl material with handles. Fastfold type screens have a sturdy rigid plastic case with pulling handles, wheels and locking straps.

Ceiling Recessed

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.

Ceiling Closure

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 a separate motor and some with a hook and latch system.

Ceiling Suspendable

Electric or manual pull down screens that can either be fixed directly to the wall or 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.

Diffusion Surface

Diffusion screens are the most common screen surface. They typically have a gain of 1.0 and a viewing angle of 50º left/right. They are best for environments which require a wide viewing angle and have a high ANSI lumen projector. The gain from the surface ensures the image appears equally bright from all angles of the room. The surface diffuses the projected light across the whole surface area.

Electric Remote

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 Radio Frequency or 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 maximum with a 60 degree operating cone.

Electric Switch

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.

Electric Motor

All our electric screens have a motor-in-roller assembly to ensure that the surface position is as 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 accessible from the screen end cap through a removable cover panel. Most of our screen manufacturers use the Somfy leading high quality brand of motor in their products.

Extension Brackets

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.

Fresnel/Lenticular

Rigid Rear Projection screens can have a Fresnel/Lenticular optical lens structure precision cast into the acrylic 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.

Fixings

Usually supplied by others, fixings are the physical screws, bolts, rawlpugs to suit the installation wall or ceiling requirements. Fixings suitable for the application need to adhere to Health and Safety regulations and be 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

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 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 conducive to benefiting from a high gain surface. Some high gain surfaces reflect the maximum gain back towards the projector, so ceiling mounting may be an issue.

High Gain Surface

Typically, these have a gain in excess of 2.0 and require a viewing angle of 25 degrees. High gain screens are best used in environments where ambient light is an issue and projector positioning is conducive to benefiting from a high gain surface. Some high gain surfaces reflect the maximum gain back towards the projector, so ceiling mounting may be an issue.

High Contrast Grey

A front projection surface that provides greater contrast and black reproduction than standard surfaces, with a lower gain to handle today's super-bright projectors. The grey colour enhances colour contrast and black levels in the projected image, and also allows for more ambient light in the audience area than on traditional surfaces.

Holoscreen

Holographic transparent screen that provides an ethereal 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.

Hotspot

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.

Integration

Where an 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 projector, selecting a source and dropping the screen all from a single wall touch panel or hand held touch panel.

IR Kit

Infra-Red Kit to control any electric screen (not including Plug and Play type screens). Consisting of a receiver, sensor and transmitter, IR Kits can be retro-fitted or installed at the same time as the screen. Operating up to 12m maximium with a 60 degree operating cone.

Lens Ratio

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 relevant to the particular model required to facilitate the minimum and maximum screen width achievable at a given Throw Distance.

Limit Switches

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 Switches, as these are known, are factory set but can be carefully adjusted if required. See manufacturers installation instructions for details.

Low Voltage Control

Where a 220 volt 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.

Multi Aspect

Electric screens that have the added benefit of an 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.

Portable Screen

A screen that can easily be moved from one location to another and is easily set up for projection.

Pull-down Screen

A screen type that is manually retracted from a screen cassette, usually fixed directly to 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.

Plug and Play

Electric screens that are pre-wired and fitted with a plug. Control can be via an Infra-Red or Radio Frequency system or an in-line control that is buit into the motor in the screen.

Projector Trigger

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.

RF Kit

Radio Frequency Kit to control any electric screen (not including Plug and Play type screens ). Consisting of a receiver and transmitter, RF Kits 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.

Rear Projection

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, fresnel/lenticular optical solutions available.

Reflective Surface

Typically, these have a gain of 2.0, and a viewing angle of 35 degrees. This surface is best used in environments with normal ambient light or a low ANSI lumen projector. This surface reflects light in the opposite direction to the projector, and therefore works best when the projector is mounted on the ceiling.

Roller

Either a steel or aluminium tube, onto which the screen fabric is fixed. 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 an electric motor assembly at the other.

‘S’ Hooks

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

Self-supporting screens feature a heavy weighted dowel or slat bar which in turn keeps the screen surface flat. The flatter the screen surface the higher the image clarity. Self-supporting screens are most common in comparison to Tensioned or Tab Tensioned screens. Matt White is the most common self-supporting fabric.

Spring Roller Assembly

Tensioned spring technology built into the screen roller that facilitates the consistent rolling up and down of the screen surface. Locking system ensures that the screen will stay down for viewing but will allow rolling up when released.

Tab Tensioned

Tab Tensioned screens feature tensioned cords on both sides of the screen to keep it flat. Many also incorporate a weighted dowel or slat bar for extra screen tension. Typically a viewer can see an hour glass shape with the tensioning cords on the sides of the surface. Surface flatness is greatly enhanced by this technology.

Tensioned

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

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 and screen. Most projector manufacturers give details on the specifications relevant to the particular model required, to facilitate the calculation of the Throw Distance achievable with the screen width and Lens Ratio.

Tripod

Portable pull up screen on a single steel column with foldable three leg construction.

Velcro or Domes (Press Studs)

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.

Viewing Angles

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 the viewing angle. Angles described in this catalogue are measured left/right.

Viewing Area

The actual section of the screen surface that the projected image is shown and directly relates to the aspect ratio of the screen. Black borders on the sides, above and below enhance the perceived visual image.

Veltex

Black velvet material that is added to the frame on Frame screens to enhance the perceived visual display by absorbing the projected light overspill.