The previous post talked about the importance of white balance, and the impact that this not-so-well-known setting has on your pictures.  This time, we'll explore the use of "custom white balance" settings to adjust the mood to fit your specific shooting needs.

Most modern cameras do a fantastic job of auto-detecting white balance about 90 percent of the time.  This is often done via a little white translucent "window" on the face of the camera which "reads" what white is, and then adjusts the exposure and color temperature of your image accordingly.  (Without getting to much into the technicalities, each shade of light has a "temperature", measured using a Kelvin scale.  For instance an incandescent light is about 2500 K, while natural sunlight is 5000 K.  You don't need to know the numbers to apply the techniques we're talking about here, but I include the reference for completeness.  

So, when does this happen?

Have you ever been at a scene and snapping images, only to get home to find out that Aunt Mabel is a sickly green, or the lazer blue car you've been eyeing appears more like sea green in the pictures?  This is all a result of a misread color temperature, either direct from the "Auto" setting on the camera, or because a setting had not been adjusted to account for a change in lighting conditions.

When shooting people under fluorescent lights, unless you make corrections or have a camera particularly good at white balance, a greenish haze is very common.  Similarly, when shooting by parking-lot-light, a deep orange color is often the norm.  

The issue stems from the camera making an on-the-spot decision.  For example, it doesn't know that the orangish sulfur lights are supposed to be white, instead thinking that it is a sunset or the like that you are trying to capture.  As a result, the camera manufacturers "bet the odds" and expose based upon what is most likely to be occurring.  To be clear, they do a great job, and 90+ percent of the time they are right on.  The problem is that other 10 percent, and often it is those situations that are a little bit outside of the norm that are particularly important.

It is at these times that a custom white balance setting is in order.  In other words, when you are trying to capture that snapshot of your soon-to-be rockin' sportscar, you know that it is nighttime, and that the yellowish overhead lights are just that, and you want them to appear as white.  In other words, just as your eyes see past the yellowish haze and interpolate the right color of the car, we want the camera to do the same.  So, how do we do it?