How to match a screen to a projector – step by step

Step 1: the projector's resolution sets the screen's aspect ratio

First check the projector's native resolution in its specification, i.e. the number of pixels on its imaging chip. This determines the format in which the projector shows an image without bars or scaling.

A screen in the same format will use the whole chip. Choose the 2.35:1 cinema format only if the projector supports an anamorphic lens or lens memory – details in the guide 16:9 or 2.35:1.

Step 2: throw ratio – what image width the projector will give

Throw ratio is the ratio of throw distance to image width. Projector manufacturers state it in the specification, e.g. 1.5:1 or – for zoom lenses – as a range, e.g. 1.3–2.1:1. The formula is simple:

image width = throw distance ÷ throw ratio
throw distance = image width × throw ratio

The distance is measured from the lens to the screen. Example: a projector with a throw ratio of 1.5 hung 4.5 m from the screen gives an image 4.5 ÷ 1.5 = 3 m wide.

Method 1: fixed distance – the projector already has its place

This method works when the ceiling mount, shelf or connections are already planned. You calculate the range of image widths the projector can produce from that position and choose a screen within that range, checking it against the viewing distance.

Example: a projector with a 1.3–2.1 zoom hung 5 m from the screen. Image width: 5 ÷ 2.1 ≈ 2.38 m to 5 ÷ 1.3 ≈ 3.85 m. If the D/6 formula says the room needs a 2.4 m width, a 2.4 m screen is within range – you set the image with the zoom.

Method 2: fixed width – screen first, then the projector position

When the screen size follows from the viewing distance, you calculate where the projector should go. Example: a screen 2.5 m wide, a projector with a 1.2–1.5 zoom. Throw distance: 2.5 × 1.2 = 3.0 m to 2.5 × 1.5 = 3.75 m. Install the ceiling mount within this range, ideally nearer the middle of the zoom range – this leaves a margin for adjustment.

It is a good idea to check both methods with the throw distance calculators provided by projector manufacturers and independent sites with projector databases. You enter the model and the image width or distance, and immediately see the zoom range and the recommended vertical position of the projector.

The screen size, however, always follows from the viewing distance – the projector merely confirms that it can “cover” it. The formulas are in the guide how to choose the screen size.

Step 3: standard, short-throw or UST projector

ADEO classifies projectors by throw distance relative to image width:

• UST (ultra short throw) – throw distance less than 0.5 × image width. Example: for an image 2.2 m wide, a UST projector sits closer than 1.1 m to the screen.
• ST and standard projectors – throw distance at least 0.5 × image width.

This distinction determines the fabric and the screen design:

A UST projector shines onto the screen at a very steep angle, which accentuates every ripple in the fabric. That is why the manufacturer recommends a fixed-frame screen (Plano, Frameless, Prestige) or a roller screen with Tensio tensioning. More in the guide screens for ultra-short-throw projectors.

Step 4: projector brightness vs screen size and gain

A projector's light output (in lumens) is spread over the whole image area. The illuminance on the screen in lux is approximately lumens ÷ image area in m². The brightness the viewer sees also depends on the fabric's gain: higher gain means a brighter image on axis but a narrower viewing angle. As a rough guide, luminance in nits (cd/m²) ≈ lux × gain ÷ π.

Worked example

A 100″ 16:9 screen measures approx. 2.21 × 1.25 m, i.e. approx. 2.76 m². A projector rated at 2000 lm produces approx. 725 lx on it.

These are theoretical calculations – in picture modes calibrated for accurate colour, projectors usually deliver noticeably less light than specified, and the lamp or laser light source dims over time. The conclusions are clear, however:

• going from 100″ to 120″ increases the area approx. 1.44 times, so the image is approx. 30% darker,
• a grey fabric with a gain of 0.5 needs roughly twice as many lumens as a white one with a gain of 1.0 to give the same brightness – in return it gives deeper blacks in ambient light,
• in a bright room an ALR fabric and a brighter projector help more than enlarging the screen.

Details in the guides screen gain and viewing angle and screens for a bright living room.

Step 5: projector position – lens shift instead of keystone correction

Ideally the projector should be positioned so that its image matches the fabric without any correction. Lens shift helps here – mechanically moving the image vertically and horizontally without loss of quality. The shift range is given in the projector's specification; projectors without this feature have a fixed image position relative to the lens (offset), which must be taken into account when choosing the mount height.

Digital keystone correction straightens the image in software, but at the expense of resolution and sharpness – some of the chip's pixels go unused. Treat it as an emergency measure. When planning installation, first set the height of the bottom edge of the image, and only then the height of the projector mount and, if needed, the length of the screen's black drop.

Step 6: matching screen and projector in practice

• 12 V trigger – many projectors have a trigger output. A motorised screen can come down automatically when the projector is switched on; see controlling a motorised screen.
• Margin for the border – a black border around the image makes alignment easier: the image can overlap it slightly without a visible glow on the wall.
• The same format in all sources – set the laptop, player and projector to the projector's native resolution to avoid scaling.

A full worked example: living room with a 4K projector

The sofa is 4 m from the wall, the living room is 6 m long, and the 4K UHD projector has a 1.4–2.24 zoom.

1. Aspect ratio: 4K UHD is 16:9 – a 16:9 screen.
2. Size: H = 4 ÷ 2.5 = 1.6 m; width ≈ 2.84 m, diagonal approx. 128″. We choose an image 2.8 m wide.
3. Throw distance: 2.8 × 1.4 ≈ 3.92 m to 2.8 × 2.24 ≈ 6.27 m. A projector on a shelf behind the sofa, 5.5 m from the screen, is within range (throw ratio approx. 1.96).
4. Projector type: 5.5 m is much more than 0.5 × 2.8 m, so it is a standard projector – Ambient Grey 2 fabric is allowed.
5. Light: a living room with windows – ALR Ambient Grey 2 fabric and a tensioned screen, e.g. OnSuperior. Viewing angle approx. 60° – we check that the outer seats on the sofa fall within it.
6. Control: the screen is lowered by a 12 V trigger from the projector or by remote.

Common mistakes

• Screen bought before checking the throw ratio – it turns out that from the only possible position the projector cannot cover the chosen width.
• Ambient Grey 2 with a UST projector – the fabric is not designed for this; choose Reference Grey 2 or Ambient Grey.
• A large screen for a weak projector – the image will be pale, especially with a low-gain grey fabric.
• Keystone correction instead of proper installation – loss of sharpness and uneven image edges.
• Screen aspect ratio different from the projector's – bars on the screen or an image spilling over the fabric.

Already have your projector's data? Enter the image width in the configurator for the home or for business and institutions.

Frequently asked questions