ALR and grey screens – when they are worth it

The problem: ambient light steals contrast

A projector cannot display black – a black area of the image is simply where the projector sends no light. How black that area looks depends on how much light reaches the screen from other sources: windows, lamps, and light walls and ceilings reflecting part of the image back onto the screen. In a dark cinema room the blacks are deep. In a living room during the day, a white fabric reflects daylight just as readily as the projected image, so black turns grey and colours fade.

There are two ways to counter this: limit the light (blinds, dark walls, lights off) or choose a surface that reflects less ambient light. This guide is about the second approach.

Grey screen vs ALR screen – the difference

A grey fabric works simply: it reflects less light in every direction. The projected image is much brighter than the stray light in the room, so after “dimming” both, the white-to-black ratio improves, especially when the problem is light walls reflecting the image. A grey fabric also keeps a wide viewing angle.

An ALR fabric (Ambient Light Rejecting) has an optical structure that reflects light coming from the projector's direction towards the audience and largely suppresses light from other directions – from the sides and above. As a result, under the same lighting it delivers better contrast than ordinary grey at a higher gain. The price is a narrower viewing angle and sensitivity to the direction of the projector's light.

Three ADEO grey fabrics

Ambient Grey 2 – the strongest light rejection

This is the only ALR fabric in the ADEO range. At gain 0.9 it keeps good brightness while being the most effective at reducing the impact of light from windows and lamps. It works well in a living room with side windows, a bright meeting room or a showroom. Limitations: a viewing angle of approx. 60° and suitability only for standard and short-throw (ST) projectors.

Ambient Grey – grey for UST and ST

Gain 0.6 and a 140° angle make it a compromise: the fabric improves the picture under ambient light and with light or coloured walls, and also works with UST projectors. A good choice for a living room with a “laser TV” standing on a cabinet below the screen.

Reference Grey 2 – better blacks in a cinema with light walls

The darkest of the fabrics (gain 0.5) with a full 180° angle. It is not an ALR fabric, but it noticeably improves blacks in rooms where light walls and ceilings reflect the image back onto the screen. It is suitable for UST projectors and comes in an acoustic version.

Why Ambient Grey 2 does not work with a UST projector

An ultra-short-throw projector stands right below the screen and lights it from below at a very steep angle. A projector is considered UST when its throw distance is less than half the image width. The structure of Ambient Grey 2 is designed for light coming from the front, from a typical throw distance – when lit from below it cannot direct the light properly towards the audience, and the image will be uneven. That is why the manufacturer specifies Reference Grey 2 or Ambient Grey for UST projectors. More in the guide screens for UST projectors.

Viewing angle – who sits at the side

A viewing angle of approx. 60° means viewers should sit in a relatively narrow sector facing the screen. In a living room with a centrally placed sofa this is usually not a problem. In a meeting room where some people sit at the far ends of the table, the image will look noticeably darker from the side. If the audience is spread wide, choose Ambient Grey (140°) or Reference Grey 2 (180°) and limit the light in other ways. The relationship between gain and viewing angle is covered in the guide screen gain and viewing angle.

Hot spot and image uniformity

Directional surfaces can show a hot spot – a brighter area where the reflection of the projector's light hits the viewer's eyes directly. The wider the viewing angle, the lower the risk of this effect. Sensible projector placement also helps – centred on the screen and at the distance given by its throw ratio, without extreme lens shift.

Flatness: ALR needs a frame or tensioning

The optical structure of an ALR fabric only works properly when the surface is perfectly flat – every ripple changes the angle of reflection and shows up as a lighter or darker band. The manufacturer recommends that roller screens with ALR fabric have Tensio tensioning, or that a fixed-frame screen is chosen. In practice this means:

• fixed-frame screens – Plano, Prestige, Frameless,
• roller screens with side tensioning – OnSuperior, and InSuperior for in-ceiling installation; see tensioned screens,
• motorised screens in the Tensio Classic version, e.g. Rugby Plus.

Projector brightness with a grey fabric

Lower gain means a darker image with the same projector. As a rough ratio: on Reference Grey 2 (gain 0.5) the on-axis image will have approx. 0.5 ÷ 1.2 ≈ 42% of the brightness the same projector would give on Vision White (gain 1.2). On Ambient Grey (0.6) – approx. half. So with a grey fabric in a bright room, choose a projector with brightness headroom and a sensibly sized image – a larger surface spreads the same lumens over a larger area.

When a grey or ALR screen makes no sense

• In a dedicated, dark cinema room with dark walls, the white Reference White 2 will give a brighter image without any loss of blacks.
• In a wide room with viewers sitting far off the screen's axis, a narrow-angle ALR fabric will not perform.
• With a very weak projector, a grey fabric can make the image too dark – it is better to limit the light in the room.
• When light falls straight onto the screen from behind the audience (e.g. a window opposite the screen), no fabric can replace blinds.

How to choose – summary

1. UST projector – Ambient Grey or Reference Grey 2.
2. Standard projector, a lot of light from the sides or above, viewers facing the screen – Ambient Grey 2.
3. Standard projector, light walls, little light, wide audience – Reference Grey 2 or Ambient Grey.
4. Speakers behind the screen – Acoustik versions.
5. With ALR – a fixed-frame or tensioned screen.

A full comparison of all surfaces is in the guide how to choose a projection fabric, and practical advice for a living room with windows in the guide a screen for a bright living room. You can put your choice together in the configurator.

Frequently asked questions