Note 007 · S3 Misconceptions · 29 Oct 2026
Brighter is not more readable — and the sun is why
A brighter wall does not read better in a room that is already bright. What changes is the black level, the glare and the electricity bill. Readability is a ratio, and only one side of it is on the datasheet.
Contrast decides readability, not nits. Our indoor fixed lines run 600 to 800 cd/m² and the outdoor Fort line 4,500 to 6,500 cd/m². Pushing an indoor wall past 800 raises black level and glare before it raises legibility, because the room cannot get darker than its ambient light.
Two walls, same nits, different result
Put a 6,500 cd/m² panel in a dim room and it is uncomfortable: the black areas of the image are lit by the panel's own ambient output, and the eye adapts to the brightest thing in the room. Put the same panel on a west façade and it reads as grey at four in the afternoon, because the glass is reflecting far more light than the pixels emit.
The number that governs readability is not brightness in isolation. It is brightness against the light arriving at the surface — the ratio between the two. A datasheet gives you one half of that ratio and, for indoor panels, gives you no way to know the other half.
The brightness ladder, by line
| Series | Rated brightness (cd/m²) | Situation it is specified for | Maximum power (W/m²) |
|---|---|---|---|
| Fortis Ultra P1.56 | 600 | Boardroom, control room, close viewing in controlled light | 350 |
| Fortis Lite P2.6 / Standard P1.95 | 800 | Lobby, retail, reception with daylight through glass | 350 |
| Flare / Fresco | 800 | Rental and feature walls indoors | 800 / 400 |
| Floor | 1,200–1,800 | Lit atrium floor, viewed from above under downlights | 640 |
| Flame | 4,500–5,000 | Outdoor rental, flown, evening and daylight events | 800 |
| Fort | 4,500–6,500 | Façade, sun-facing, viewed from the far side of a road | 650–800 |
Brightness and power are both from the series sheets; power rises with brightness within the same line, which is why the nits are not a free upgrade.
The rule, stated as a ratio
If ambient light on the glass is low, then 600–800 cd/m² is enough and more nits reduce legibility. If the surface is in direct sun, then the panel rating is only half the answer and the reflectance of the glass decides the rest.
Note what the rule does not say: it does not say a higher-rated panel is worse. It says that above the light level in the room, additional nits stop being converted into legibility and start being converted into glare, halation around bright objects and a higher electricity bill per square metre.
Where the claim does not hold
1. The wall is seen from far away. At 30 m across a road, the eye cannot resolve the black level and only the emitted light matters. There, more nits really do read better — the rule above is a near-viewing rule.
2. The content is dark by design. A wall showing dark footage in a bright room needs headroom rather than average brightness, because the highlights carry the image. Judging it by a full-white nits figure flatters or condemns the wrong thing.
3. The room's lighting is under your control. Dimming the room by half does more for readability than adding 200 cd/m², and it costs nothing. If the lighting design is not fixed yet, fix that first.
4. The panel has a low-brightness mode with poor grey scale. Running a bright panel dimmed is only an advantage if the driver holds its grey scale at low output. Our indoor sheets specify 14 or 16 bit grey scale, and that is the specification that makes dimming usable rather than merely dim.
One thing we got wrong ourselves
We used to compare walls by their nits figure, and to recommend the higher one when a client complained about readability. In a lobby the complaint is almost always about reflected daylight or a badly lit ceiling, and the higher-brightness panel made both worse. We now ask what is reflecting off the glass before we discuss a number.
- Datasheet — Series sheets: Fortis 600 cd/m² at P1.56 and 800 cd/m² at P2.6 and P1.95, 350 W/m² maximum, 14 or 16 bit grey scale; Flare and Fresco at 800 cd/m² minimum; Floor at 1,200–1,800 cd/m² with 640 W/m² maximum; Flame 4,500–5,000 cd/m² at 800 W/m²; Fort 4,500–6,500 cd/m² at 650–800 W/m².
- Practice — The perceptual convention that legibility follows the ratio between emitted and ambient light rather than emitted light alone. It is a working principle used across display engineering, not a certified measurement method.
Questions we get on this
Yes — outdoors, from a distance, or in a room you cannot dim. The claim is narrower than “brighter is bad”: indoors at close range, above the ambient level, extra nits cost money and comfort without buying legibility.
The lowest rating that holds up at the worst hour of the day, plus the grey scale that lets it dim cleanly, plus a lighting design that keeps daylight off the glass. On our indoor lines that usually means 800 cd/m² and 16 bit.
Driving at a higher current does, in principle. Our sheets do not publish a lifetime figure by brightness setting, so we do not quote one — that number stays TBC until we have the data.
Send a photograph of the wall at the worst hour.
We will tell you the brightness rung it needs and the room conditions that would change the answer — in writing, with the site measurement we still need named.