"This Corridor Is Too Dark."
20 footcandles on the floor, code compliant, IES-recommended levels met — and the client still said it was too dark.
4.29.26
Early in my career, I worked on a project with a restroom corridor adjacent to a three-story atrium. The atrium had a large curtain wall that flooded the space with daylight. The corridor was hitting 20 footcandles on the floor, which met or exceeded every applicable standard. On paper, the lighting was fine.
In person, it didn't feel fine. People walking from that bright, daylight-filled atrium into the corridor perceived it as uncomfortably dark — not because of the actual light level, but because of the contrast between the two spaces. The human eye adapts to the brightest thing it sees, and when you transition from a sunlit atrium to an interior corridor in a few steps, 20 footcandles feels like a cave.
I'd also specified hyperbolic trims on the recessed downlights in that corridor. Hyperbolic trims are designed to reduce the visible brightness of the aperture — they make the ceiling look cleaner and more refined. In many applications, that's exactly what you want. But in this case, it worked against us. Because the fixtures were less visible in the ceiling, occupants couldn't see the light sources themselves, which reinforced the perception that the corridor wasn't adequately lit. The light was reaching the floor, but the ceiling looked dark and inactive.
It was a good lesson learned early. Two things I took away from it that I still carry into every project:
First, light levels in any given space don't exist in isolation. A space that reads as appropriately lit on its own can read as too dark or too bright depending on what's next to it. Transition zones — corridors adjacent to atriums, lobbies adjacent to exterior glazing, interior rooms adjacent to brightly lit open offices — need to be designed with the adjacent condition in mind, not just the numbers for that room.
Second, how occupants perceive the light source matters as much as the light it produces. In spaces where reassurance is part of the goal — where people need to feel that the space is well lit — fixture visibility can be a feature, not a flaw. A clean, quiet ceiling is sometimes the right call. But not always.
Lighting design isn't just about putting the right number of footcandles on a surface. It's about how the whole project works together — space to space, transition to transition — and how people experience that sequence in real time.
