The purpose of ambient light is to create a diffused, even light level in a room, and it's the first place to start when creating a lighting scheme. Ambient light can also refer to a lighting scheme as a whole, but for our purposes, we'll be talking about ambient light sources. The source usually comes from lights on the ceiling, though sometimes table or floor lamps can do the trick. Overhead light sources can be a lone bright light, such as a ceiling or pendant light, or multiple lights, such as track lighting or recessed cans. These smaller lights all work together to create the main light source, but the difference is that they can be aimed at different areas of the room to get into all of the nooks and crannies.
Most overhead lights use incandescent bulbs, which are inexpensive and come in a variety of wattages. Compact fluorescent bulbs also have come on the scene as "green" alternatives that cost a little more but last considerably longer than their incandescent counterparts. They also have the benefit of being recyclable, whereas regular light bulbs are not. The downside is that fluorescent lights have a reputation for casting unattractive light, but manufacturers are continually working to improve this. No matter what bulb you use, overhead lighting is practical but it can be garish, so ambient light sources need to be complemented with other kinds of lights to provide contrast. In the next section, we'll talk about accent lighting.