What I learned in my Digital Photography class, Part 10
Now here's a subject that was all new to me, easily understood, and very useful to know. You know how sometimes the color in your photos just seems a bit off? Perhaps there is a strange cast to the colors that you know wasn't there when observed by your own eye?
That's because we are taking photos under a variety of light conditions. Your camera will not always see "white" as the pure "white" you want it to be (although our own eyes tell our brain that the white is white), depending on the light source--sunshine, shade, artificial light, etc. We can make the assumption that if white looks right in your photos, the other colors will, too.
You can deal with this "white balance" by doing one of three things: Leave the white balance on "auto" and take what you get, choose to set the camera's white balance from a variety of choices, or set up a custom white balance.
My camera gives the following choices, in addition to auto and custom: Daylight, shade, cloudy/twilight/sunset, tungsten, white fluorescent light, or flash--each has a little icon that shows up when I press the shutter halfway, so I can see what setting I have already chosen. I find all these choices on the white balance menu, and you will, too, once you check your manual to locate the menu.
If you choose, instead, to set up a custom white balance, you shoot a white object that will serve as the basis for the white balance setting. By selecting this image, you import its white balance data for the white balance setting. (Quoted from my camera manual).
There! That's white balance, and now that you know about it, you should find that the colors in your photos will look a little truer to your eye.
If you would like to read more about this issue and see some photos illustrating how different settings affect results, read this photo.net article on White Balance by Jon Sienkiewicz.