Dark colors absorb light, and so dark carpets, ceilings, curtains, furniture, or walls may limit the amount of light in rooms. But pale-colored walls and furnishings reflect light back into a room. A lamp shade distributes the light from a bare bulb and shields the bulb from direct view. The shade directs light downward toward the seeing task and upward to help light the room. Opaque shades send all the light up and down, but translucent shades transmit some light to the room.
Colored shades tend to color the light.
For this reason, shades with white or near white linings should be used. Efficient use of lighting can conserve energy. Different types of lighting can provide different amounts of light while using the same amount of energy. For example, incandescent lamps provide about 20 lumens per watt, while fluorescent lamps provide 70 lumens per watt. Engineers and scientists are continually looking for ways to improve the efficiency of lamps.