Projector screen gain explained
What screen gain really does to brightness, with a computed table. Most ambient-light-rejecting screens sit below 1.0 — darker than plain white.
Gain is how much light a screen reflects back compared with a reference matte-white surface, which is defined as 1.0. A 1.5-gain screen sends about 50% more light toward the centre seat; a 0.6-gain screen sends 40% less. The counterintuitive part: **most ambient-light-rejecting screens have gain below 1.0**. Across the 24 ALR and CLR screens we track, 15 of them — 63% — are darker than plain white. CLR screens for ultra-short-throw projectors sit around 0.6. They buy contrast by rejecting light from the sides and ceiling, and they pay for it in brightness, so they need a brighter projector, not a dimmer one.
Gain is a trade, not a free upgrade. A high-gain screen is more directional: it concentrates light toward seats on the centre axis, and viewers off to the side see a dimmer, sometimes uneven image — the effect called hotspotting. A low-gain screen spreads light evenly and holds black levels better in a room with lamps or windows, which is exactly what ALR and CLR materials are engineered for. That is why the premium screen in a bright living room is usually the darker one. Size the projector for the screen you actually chose: multiply its lumens by the gain before comparing against what the room needs.
What gain does to on-screen brightness
| Gain | vs plain white | 3 000 lm on 100″ | Typical of |
|---|---|---|---|
| 0.5 | -50% | 545 lx | CLR screens for UST |
| 0.6 | -40% | 655 lx | CLR screens for UST |
| 0.8 | -20% | 870 lx | Darker ALR |
| 1.0 | — | 1090 lx | Plain white / matte |
| 1.2 | +20% | 1305 lx | Typical ALR |
| 1.5 | +50% | 1630 lx | High-gain, centre seats only |
Frequently asked questions
Related guides
ALR vs CLR screens
The two are not grades of the same thing, they reject light arriving from different directions, and the right one is decided by where your projector sits. A **CLR** (ceiling-light-rejecting) screen has a horizontal sawtooth structure that only works with light coming from below — that is, from an ultra-short-throw projector on a cabinet. An **ALR** screen rejects light arriving off-axis and suits a short-throw or standard projector further back. Put a UST projector on an ALR screen and you get a washed-out hotspot. Of the 110 projectors we track, 29 are ultra-short-throw (throw ratio below 0.4) and need CLR; the other 81 do not. And the number on the box will not help you tell the materials apart: across our 24 screens, CLR runs 0.5–1.0 gain and ALR runs 0.8–1.65, so 9 of them — 38% — sit in the 0.8–1.0 band where both types exist.
GuidesHow many lumens do I need?
Lumens needed scale with screen area and ambient light. As a rule of thumb, a 100-inch screen needs about 600 lumens in a fully dark room, around 1,300 for a living room with some light, and 2,700+ for a bright room. Bigger screens and more light need proportionally more.
GuidesProjector vs TV
A projector wins on sheer size and cost-per-inch — 100 to 200 inches for the price of a much smaller TV — but needs controlled light or an ALR screen. A TV wins on brightness, convenience and lifespan. For movie nights on a big screen, choose a projector; for all-day bright-room viewing, choose a TV.
Updated