Ambient lighting is natural lighting provided by windows supplemented by ceiling- or wall-mounted luminaires at various times. However, it is supplied artificially by lamps and luminaires at night. Floor and table lamps, considered to be task lights, usually cannot be the prime sources for ambient lighting at night because of their limitations and the fact that they leave parts of the room in darkness. The amount of ambient light required in a room depends on the activities that take place in that room and the color of its walls. Dark walls absorb more light than white or off-white walls, increasing the lumens required. Kitchens and bathrooms need bright, uniform ambient lighting, but more subdued ambient lighting is acceptable in bedrooms and hallways.

Task lighting from floor, table, and desk lamps supplements ambient lighting by providing secondary light to rooms for occupants performing some activity calling for high visual acuity, such as reading, sewing, preparing food, shaving, or applying makeup. Task lights are positioned to illuminate kitchen and bathroom counters and sinks, desks, and workbenches. The sources can be incandescent, halogen, or fluorescent lamps.

Kitchens require direct light on countertops where food is being prepared. This can be achieved with lamps mounted under kitchen cabinets, recessed ceiling lamps, or ceiling-mounted track lights focused on counters. Supplemental light on range tops can give shadow-free illumination on food being prepared. Kitchen task lighting should have color tones that make food appear as natural as it...