<p>The reflectance indicates how many percent of the light falling on a surface is reflected. Brightsurfaces have a high dark surfaces have a low reflectance: White walls reflect up to 85 percent of the light, a light wooden paneling up to 35 percent, red bricks on the other hand only up to 15 percent. Conclusion: The darker a room is arranged, the more light is needed to achieve the same illumination on the working plane.</p>