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Why brightness gets noticed only after it's too late
Brightness is the spec nobody thinks about in the demo room, because the demo room has controlled lighting. Then the panel goes into a real classroom with a wall of windows, or a meeting room where the blinds get left open, and by 2pm the screen looks washed out. The panel still works — it just looks dim and tired, and everyone squints at it for the rest of the day.
That's what brightness actually determines: whether the panel stays readable in a lit room, not just in a dark one. And it's measured in candela per square metre — usually written cd/m², or "nits." The question worth asking before you buy isn't "does it have a bright screen" but "how bright, and is it enough for the room I'm putting it in."
What the number actually means
Brightness is how much light the panel pushes out. More nits means the screen wins against ambient light — windows, overheads, skylights. A panel that's too dim gets overpowered by the room, and no amount of software fixes that; it's a physical property of the backlight.
For a classroom or meeting room, the practical standard is 350 cd/m². That's bright enough to stay readable with the lights on and curtains half open, without being so bright that it's harsh to look at up close. Panels that dip below that — into the 250–300 cd/m² range — start to look grey and flat in a lit room, and buyers notice it the first sunny afternoon.
Brightness isn't the whole picture
Two things work alongside brightness, and they're easy to confuse. Contrast ratio is how much difference there is between the brightest white and the darkest black — a panel with good contrast looks sharper even at the same brightness. And an anti-glare coating stops the screen turning into a mirror under overhead lights, so the brightness you paid for actually reaches your eyes instead of bouncing back as a reflection. We covered the coating side in our guide to interactive flat panel screen durability.
The point: brightness, contrast and anti-glare are a package. A panel with high nits but no anti-glare coating still washes out, because the light reflects before you see it.
How to verify brightness before you buy
Brightness is one of the easiest specs to fudge on a datasheet, and one of the easiest to check in person. Three things to do:
1. Ask for the number in cd/m² or nits, not "bright." "High brightness" means nothing; 350 cd/m² means something specific.
2. Look at the panel in a lit room. Not a dim demo booth. Turn the room lights on, stand a few metres back, and see if text stays readable.
3. Check the anti-glare claim. If the panel advertises brightness but no anti-glare treatment, the number won't hold up in a windowed room.
How Lonton specs brightness
Lonton has been manufacturing interactive flat panels since 2005 from a 100,000-square-meter facility with 15 production lines. Our panels ship at 350 cd/m² with an anti-glare coating, so a classroom or meeting room stays readable with the lights on — not just in a dark demo. If you're also weighing eye comfort for long teaching days, our guide to eye safety and blue light covers that side.
Get a panel bright enough for your room
Tell us your room, its lighting and how it's used — and we'll confirm the panel's brightness is right for the space, with a factory-direct quote. Contact Lonton or browse our interactive flat panels.
Frequently asked questions
How many nits should an interactive flat panel have?
For a classroom or meeting room, 350 cd/m² (350 nits) is the practical standard — bright enough to stay readable with the lights on.
Is 350 nits bright enough for a classroom?
Yes. 350 nits with an anti-glare coating keeps the screen readable through the day, even with windows and overhead lights.
What is the difference between brightness and contrast ratio?
Brightness is how much light the panel outputs. Contrast ratio is the difference between the brightest white and darkest black — good contrast looks sharper at the same brightness.
Why does an interactive flat panel need anti-glare?
Anti-glare stops overhead lights turning the screen into a mirror, so the brightness you paid for reaches your eyes instead of reflecting away.
