White is the color we know to reflect the most light off surfaces, so we paint our walls and ceilings bright white to give more luminance to the room. Most often we cover our floors with carpets and rugs not thinking that the surface area of the floor contributes to the light reflectance in a room. Rooms as above show how much brighter and more spacious rooms are when the floors are painted white.
When I did a course in measuring the amount of light needed in a space, particularly in a work space, we had to work out all the surface area of the walls, ceilings and floor, multiply it all together, divide by... yes, it was very geeky. It was very good in that it taught me about lux, lumens, illuminance, photometry, watts, amps and the technical and practical parts of lighting. From this course I learned how important the floor is in adding light to a space. And Edward Hopper, well he shows the poetry of light splashed across the floor.