First of all, you should know what white balance refers to: not all light sources are pure white like the midday sun. If you want to get the right colors in your photo, pay a bit of attention to the “color temperature” of the light source. Most of all, this is important in portrait and people photography because of the necessity of having accurate color of the skin.
Warmer sources (incandescent, candles, sunsets, and sunrises) will create a yellowish environment, while, at the other side of the spectrum, colder sources create a bluish environment. (However, on the Kelvin temperature scale this is the opposite: warmer means bluish.) Some people like warmer color tones and Im one of them, but, it depends on the situation.
Curios to know more about color temperature? Heres an article with complete information on this aspect.
Auto White Balance
In most of the cases, the Auto White Balance of all cameras works pretty well. If shooting in JPEG and the auto white balance accidentally didnt got the colors right, there is not much to do later in the photo manipulation stage. But shooting in RAW mode allows changing the white balance after the shooting (simply click on a neutral reference within the image).
Situations when auto white balance will not likely work proper are: beaches (yellowish tin), snow (bluish tin), cloudy weather, indoor photography, but also forests. This is why a lot of cameras have scene modes for these cases.
Preset White Balance
Digital cameras also have presets white balance options: sunlight and cloudy for outdoor and fluorescent, incandescent and tungsten bulb for indoor in case you need them. These will compensate the yellow or blue tint. Here are some examples for these on Canon PowerShot A520, indoor conditions.
Custom White Balance
As for manual (custom) white balance, the first question to be answered is when to use this feature?: the camera sensors appear to have white balance problems in low light, because it can not find a white or light grey (around 18% grey) reference. More than that, if a light bulb is the lighting source of the environment, the surrounding will have warmer colors than the reality (a yellow cast).
On manual white balance, you need to set up the camera using a white paper or white wall or anything else that is white or light gray around you. Once you have the white surface in your LCD, pres OK or SET depending on your camera manufacture. A better change of getting this right is to have the entire picture frame filled with the specific light grey area and nothing else in it (so move closer, get the object closer or use zoom) or at least in the center (these requirements vary from a camera manufacture to another). Then you can take your shot to the subject. The trick is to obtain the correct white balance for the subject, while the background doesn’t matter too much. Don’t use glossy surfaces when setting the white balance manually.
Other White Balance Tricks
Heres a trick you can try with manual white balance: instead of setting the white balance on pure white, do so on a vibrant color and then shoot in black and white mode. Interesting results may occur. Also, a late evening effect can be obtained by shooing outdoor with tungsten.
White Balance can also be adjusted with filters (this is more useful for film photographers). Below is an offer for ExpoDisk of 77mm and 62mm diameter. It is a neutral diffusion filter that gathers ambient light from 180Â° and passively transmits 18% of it through to your camera’s light meter. The resulting “grey frame” accurately represents the average colorcast of the light. From this grey frame, you then can set a custom white balance that result in accurate color in most lighting conditions.