Simply put, white balance controls how ‘’warm’’ or ‘’cold’’ your image will appear.
Your camera will try its best to make the white colour appear white and not overcast with blue or orange shades. Depending on the light it detects, it will determine if it’s sunny or shady and it will try to counterbalance the overcast colour in order to achieve a realistic presentation of what you see.
Now, you have a few options when adjusting this setting. Your camera will normally give a few preset options, e.g., sunlight, shade, cloudy, lightbulb, fluorescent light, manual, or auto.
What these settings are doing is basically telling your camera that what it sees is either warm or cold, so that the camera will counter the effect and make it so that the colours appear as real as possible.
For example, if you set it to cloudy, the camera will understand that what you are seeing with your eyes is ‘’cold’’; thus, it will try to balance it and make it slightly ‘’warmer’’ in order to bring it to the most natural point.
White balance set to Cloudy. White balance set to Auto.
In manual mode, you can dictate how much ‘’warmth’’ or ‘’cold’’ the camera will give to the picture. You will notice that it measures that range in Kelvin degrees. The higher the number, the ‘’warmer’’ the picture will appear and vice-versa.
For example, if you want to make the sunset look a bit warmer, or more yellow, you can set it to manual and increase it until you reach the result that you’re aiming for.
The good thing with white balance is that when you shoot in RAW format (and you should!), you can always adjust it to your preference with just one slider, without any trouble.