White balance may not be something that is thought of when calibrating your camera for a photo, but it is a very important and often not well understood topic in digital photography. I find myself taking well composed winter photos only to look at the end result and wonder "Why is my snow so blue?" The answer to that and other color anomalies in photos lies in proper white balance calibration. Understanding white balance can be incredibly tricky, because it delves into the realm of physics and science, but I will keep it condensed.
In simple terms white balance deals with color temperature. A low color temperature shifts color towards reds and a high color temperature will shift colors towards blues. Different light sources emit light at different temperatures, hence different hues cast in different photo situations.
Manually Setting White Balance:
This can be done every single time you take a photo or are taking several with a given light source. There are a couple ways to do this. First, you could purchase white balance cards, or even use paper of a particular color, focus your camera on that, and adjust the white balance accordingly so the paper appears white in those lighting conditions. Second, you can use something present in your scene to calibrate the white balance. This could be snow, a wall, a piece of sky without detail or color. To do this you need to have your ISO setting as low as possible (to reduce noise), and calibrate your white balance according to that particular part of the scene your are focusing on.
Auto White Balance:
Taking advantage of the AutoWhite Balance (AWB) setting is by far the easiest way to take account for the white balance of your scene. It works by evaluating the scene through the lens and averaging the light temperature it takes in. Then with the average light temperature it chooses a white balance settings accordingly. Most often this works fine, however there are several instances where it may not.
When what you are photographing has a large amount of warm colors, such as reds, yellows, and oranges, the AWB setting may falsely detect the colors as a warm light temperature instead and choose a white balance setting with more blues to offset the warm colors. However, when this happens the photo will appear with an unattractive bluish/cool tint. The same applies to excessive cool colors, except the camera will choose a white balance settings with more yellows and the photo will have a warmer tint.
Same scenes. Two different white balances.
The other White Balance Settings:
|Image Credit: CambridgeinColour|
Every digital SLR today, and most other digital cameras, come with several white balance settings that you can choose from given the varying light of your scene. Take advantage of these. Basically each setting is a preset based on the color temperature of a given light source. Auto white balance and custom (or manual) are discussed above. The Kelvin setting takes into consideration a a greater temperature scale when evaluating the light. I have not had a lot of success using this setting. True with all presets, there may be instances where using a preset in a given situation still does not produce the best result.
If All Else Fails:
Shoot in RAW format. RAW format, if you aren't familiar, is a very large file that contains complete color spectrum for the photo. It saves all the data and allows you to edit it later. With a RAW file you can easily load it into an editing program, aka digital darkroom, (Lightroom for example) and tweak every little color setting. Castings of unwanted yellows and blues can be finely tuned into whites with a few mouse clicks. If you have the software and ability shooting in RAW is a great fail safe for multiple minor miscalculations in camera settings.