White light is a combination of all the colors of the spectrum, as you've seen when playing with a prism or looking at a rainbow. As such, it's not going to always be white while you're filming—a myriad of factors can make images appear with a colored cast, leading to video footage that looks a little too green, or blue, or any number of shifts.
Your camcorder automatically adjusts to compensate for this color temperature of the light by setting the white balance. Essentially, this is the color that the camera sees as white, causing the camera to adjust the display of the rest of the colors based on this setting. You probably have a few basic controls for changing the setting, such as Auto, Indoor, or Outdoor presets (Figure 4.3).
Figure 4.3 Many camcorders feature the capability to adjust the color temperature they display.
You may also be able to specify the white point manually by selecting Manual and filming a sheet of white paper in the environment where you'll be shooting; the camera uses the values it captured as the basis for displaying the other colors.