White balance was something I learned about pretty late in the game. It's a shame because its not a difficult concept to wrap your head around.
Basically, the white balance of your camera and photo affect how accurate the colors in your photo are. If you read my post about how different elements affect a great photo, then you'll know there are types of light from a cool, bluish light to warm yellow tones. This can affect the temperature, mood and subject of your photo.
To set the white balance so it is at its most accurate, all you have to do is shoot a photo of the whitest object in the most accurate light as possible. Taking a photo of a piece of paper in natural light or a white wall will usually suffice. (More serious aficionados can invest in a white balance card like this one.) This tells your camera what kind of standard it should use for "white," and in turn, what kind of standard it should use for other colors along the spectrum. Though it'll vary depending on your camera model, most models have an inbuilt function within their settings to reset the white balance.
Darren Rowse from the Digital Photography School does a great job of explaining why there are often differences in 'temperature' amongst a set of photos:
The reason for this is that images different sources of light have a different 'color' (or temperature) to them. Fluorescent lighting adds a bluish cast to photos whereas tungsten (incandescent/bulbs) lights add a yellowish tinge to photos.
It's not something most people are trained themselves to look for because it's such a habitual instinct for most people to make the adjustment all on their own. To make the differences slightly more obvious, I've edited this photo to show how an unnatural white balance can affect a photo. The truest white balance-with the most accurate color representation of the object-occurs in the middle.
All stuff good to know. Don't you want to learn how to make those Fiji pictures pop when you look back at them in five years?
