Surface Reflectance vs. Direct Lighting Illuminance

Direct downlighting is an efficient way to achieve target illuminance. The final illuminance and perceived brightness are influenced by interior surface finishes, which can impact how light reflects and bounces. Using the same number of downlight luminaires and outputs, spaces with lighter finishes tend to reflect more light, enhancing the room’s brightness. In contrast, darker finishes absorb light, diminishing overall brightness and creating a more pronounced contrast between the light fixtures and interior surfaces.

Study Results

Ceiling 0.8, wall 0.8, floor 0.8: avg 45 fc at floor

Ceiling 0.8, wall 0.5, floor 0.5: avg 39 fc at floor

Ceiling 0.8, wall 0.2, floor 0.2: avg 21 fc at floor

Ceiling 0.5, wall 0.8, floor 0.8: avg 34 fc at floor

Ceiling 0.5, wall 0.2, floor 0.2: avg 20.6 fc at floor

Ceiling 0.2, wall 0.8, floor 0.8: avg 28 fc at floor

Ceiling 0.2, wall 0.5, floor 0.5: avg 23 fc at floor

Ceiling 0.2, wall 0.2, floor 0.2: avg 20 fc at floor