The screen is half of every projection system: it decides how much of the projector's light reaches the audience, how wide the good viewing area is and how well the image survives room lighting. For most meeting rooms and classrooms a matte white screen with gain around 1.0 is the safe choice; in bright rooms an ambient-light-rejecting (ALR) screen matched to the throw type can be worth thousands of lumens; for edge-blended canvases, low-gain surfaces avoid visible hot spots. This guide explains gain, viewing angle, ALR types, materials and sizing so you can specify the screen and the projector together.
Key takeaways
- Gain compares a screen's on-axis brightness to a matte white reference (1.0); higher gain narrows the good viewing angle.
- ALR screens reject light from above or the side, but each type is designed for one throw geometry — match it to UST or standard throw.
- Choose gain around 1.0 for wide rooms, blended canvases and mixed seating; consider 1.2–1.5 only for long, narrow rooms.
- Size the screen from the farthest seat first, then calculate lumens for that screen — never the other way round.
Screen gain and viewing angle
Gain is the ratio of a screen's brightness, measured straight on, to that of a standard matte white reference. A gain 1.3 screen returns about 30% more light to a viewer sitting on the axis; a gain 0.8 grey screen returns less light but deepens blacks. Gain is not free light: it is redistributed. The more a screen concentrates light toward the centre, the faster brightness falls off for viewers at the side.
That fall-off is described by the half-gain angle — the viewing angle at which brightness drops to half the on-axis value. Matte white screens have very wide half-gain angles; high-gain screens narrow it. In a wide classroom or boardroom, a narrow viewing cone means the side seats see a noticeably dimmer and less uniform image.
| Gain | Character | Best for |
|---|---|---|
| 0.8–0.9 (grey) | Deeper blacks, slightly dimmer | Bright projectors in rooms with some ambient light; high-contrast video |
| 1.0 (matte white) | Even brightness, widest viewing angle | Most meeting rooms, classrooms, edge-blended canvases |
| 1.2–1.5 | Brighter on axis, narrower angle | Long, narrow rooms with central seating |
| 2.0 and above | Very bright on axis, visible hot spot | Special cases only; avoid for wide audiences and blending |
Ambient-light-rejecting (ALR) screens
ALR screens use an optical surface structure to reflect light arriving from the projector's direction toward the audience while absorbing or deflecting light from other directions — typically ceiling lights and windows. In a lit room they raise contrast dramatically, which can be equivalent to a large increase in projector brightness.
- UST ALR screens accept light from steeply below (the ultra-short-throw projector sits under the screen) and reject light from above. They do not work with ceiling-mounted standard-throw projectors.
- Standard-throw ALR screens accept light from the front or slightly above and reject light from other angles. They do not work with UST projectors.
- Viewing angle — most ALR surfaces have narrower viewing cones than matte white; check the half-gain angle against your seating width.
- Size and flatness — ALR screens are usually fixed-frame and tensioned; rolled formats can introduce waves that the optical surface makes visible.
Screen formats: fixed, motorised, tensioned, portable
| Format | Strengths | Watch-outs |
|---|---|---|
| Fixed frame | Flattest surface, sharp black border, compatible with ALR | Permanently occupies the wall |
| Motorised (tab-tensioned) | Hides away in ceiling or wall; flat when tensioned | Needs power and control integration; budget more |
| Manual pull-down | Low cost, simple | Can wave or curl at the edges over time |
| Portable / tripod / fast-fold | Events, rental, temporary rooms | Set-up time; uniformity depends on tensioning |
| Projection board or painted wall | Classrooms with interactive UST | Must be flat and matte; glossy whiteboards create hot spots |
Special surfaces: acoustic, rear and blending screens
- Acoustically transparent — perforated or woven screens let loudspeakers sit behind the image, typical in auditoriums and cinemas. Fine perforations reduce gain slightly; with small pixels, check for moiré patterns at the chosen resolution.
- Rear projection — the projector sits behind a translucent screen, hiding equipment and avoiding shadows. Rear screens have their own gain and viewing cone; brightness falls off quickly for off-axis seats with high-gain rear materials.
- Edge-blended canvases — use low-gain (around 1.0 or below), very uniform surfaces. High-gain screens make each projector's hot spot visible and the blend zones harder to hide; see the edge blending guide.
Sizing the screen
- Measure the distance to the farthest seat and set image height to about one-sixth of it for presentation content (one-eighth for video only).
- Match the aspect ratio to the main source: 16:10 for laptop-driven rooms, 16:9 for video-driven rooms — see the resolution guide.
- Keep the bottom of the image about 1.0–1.2 m above the floor where people sit, so heads do not block it.
- Check the throw distance and mounting for that image size with the throw distance guide.
- Calculate lumens for the final screen area and gain.
| Diagonal | 16:10 width × height | 16:9 width × height |
|---|---|---|
| 100" | 2.15 × 1.35 m | 2.21 × 1.25 m |
| 150" | 3.23 × 2.02 m | 3.32 × 1.87 m |
| 200" | 4.31 × 2.69 m | 4.43 × 2.49 m |
| 250" | 5.38 × 3.37 m | 5.53 × 3.11 m |
| 300" | 6.46 × 4.04 m | 6.64 × 3.74 m |
Matching screen and projector
| Room | Screen | Projector example |
|---|---|---|
| Classroom, interactive | Flat matte projection board, 85–100" | PSE-4200UST |
| Classroom, bright windows | UST ALR screen | PSE-3800UST or PSE-4200UST |
| Boardroom, lights on | Matte white 1.0 or standard-throw ALR, 100–120" | PSL-4500U |
| Training room | Fixed or motorised matte white, 130–150" | PSL-5000U |
| Auditorium / blended canvas | Low-gain, uniform, often acoustically transparent | PSP-10000, PSP-12000 |
Common screen mistakes
- Projecting onto a glossy whiteboard and fighting the hot spot with more lumens.
- Buying a UST ALR screen for a ceiling-mounted projector (or the reverse).
- Choosing a high-gain screen for a wide room and leaving side seats with a dim image.
- Ordering the screen before confirming the throw distance and lens-shift range.
- Forgetting black borders — a dark frame improves perceived contrast and hides small alignment errors.
Recommended models
Frequently asked questions
Questions on this topic
What screen gain should I choose?
Are ALR screens worth the cost?
Can I use an ALR screen with any projector?
Can I project onto a wall?
Specifying screens and projectors together?
Send room dimensions, seating layout and lighting — we recommend screen type, size and the projector that matches it.