Understanding Digital Cameras white Balance

I don’t intend to dig deeply into color theory in this blog post on the theory of digital cameras‘ white balance; there are semester-long classes at the university for that, so we will need to take some things at face value. We need to understand that light – any light – has a color cast to it. We prefer the color cast of daylight, and we tend to use this as a standard.

What is White Balance?

The next thing we need to know is that the very best white balance tool in the world is between our ears. Our eyes look at scenes under various colors of light, and yet our brains quickly adjust the information to make whites white and gray. For example, right now, I am under fluorescent lighting, looking at a white sheet of paper. I know that the fluorescent lights have a greenish color cast and this piece of paper appears slightly light olive in color under them. However, my brain is filtering out that color cast, and the paper is snow white.

There are two simple ways to tackle the white balance problem when shooting a picture. The first is to leave the camera in its factory set AWB setting, which stands for ‘Auto White Balance.’ Engineers who know a lot about white balance have programmed the camera to handle the problem with decent results. The second way to attack the color cast caused by off-color light is to overpower it with pure white light, such as with a flash. 

There we have two simple techniques to help prevent a poor color cast in our images. And the first technique requires that you do nothing, leave the camera set as it came from the factory; how simple is that?

If it were that easy and automatic, this would be a short article, wouldn’t it? Then it should come as no surprise that the simple methods don’t always work that well. The AWB settings programmed into your camera are best guesses made by brilliant people who never have to shoot a picture in your specific living room. The flash in your camera loses its ability to overpower badly colored room lighting as the distance between the camera and the subject increases. The clean white flashlight is overpowering for only about four to seven feet, with most built-n flashes on DSLRs or on any compact camera.

At this point, we can stop and catch our breath as we get a feeling for digital cameras’ white balance functionality. When it comes to the 90% of people who are shooting family pictures in their living room, well, they don’t care if colors are ever so slightly off in their photographs. But what if you are picky or the event is essential, or if you intend to show off your pictures, how do you overcome white balance problems?

On many compact cameras and all DSLR cameras, there are several white balance settings to choose between. There are settings for incandescent lights, fluorescent lights, shady spots, cloudy days, camera flash, and more.

If AWB is automatic, these other white balance settings are semi-automatic. The photographer must choose to use these alternate settings, but a different set of program instructions are in charge after that. White balance issues are controlled automatically but biased for the specific situation. The first step toward better colors in your pictures is choosing to use these alternate white balance settings. There is a word of caution, though; these settings don’t automatically revert to AWB after the camera is turned off. The photographer must be aware of what white balance setting is being used or a problem. Usually, what happens is that the last time the camera was set for incandescent lights and not changed back to AWB, now outside on a sunny day, all of the pictures are blue! Use the alternate white balance settings but learn what your camera is telling you on its LCD screen!

A significant advantage in white balance control belongs to the DSLR group of cameras. With the more advanced digital cameras white balance controls available in a DSLR, the photographer can easily create and use their white balance setting. Tools such as white balance lens caps or filters, white or gray cards, and even three-dimensional control targets allow the DSLR photographer quick access to a better white balance setup.

Now here is the thing about white balance control ‘you have to want to do it. It is always an extra step or two before shooting and again in post-processing. However, the results can be a significant improvement to color, especially skin tone. When whites sparkle, the eyes of people in a photo look more precise and sharper. Wedding dresses look snowy rather than dingy. Colors in the surrounding environment look crisp and not muddy.

Learning to exercise control over the digital camera’s white balance is an intermediate skill. It isn’t tricky to master, and it will improve your images noticeably. If you are a compact camera shooter, learn to use your camera’s built-in alternate white balance modes. If you are a DSLR shooter, do the same and learn how to use a white balance target or set a custom white balance with a WB lens cap or filter. AWB auto white balance is pretty good, but it only takes a little effort to take a step toward spectacular. 

This photograph features an interesting pattern of ancient bricks, blocks, and stone. It even features what looks like marble blocks that were used to repair the weathered and aged wall. There is no distinct pattern in this background texture image.

Advanced White Balance Lesson

The final (advanced) lesson on white balance is that if you shoot RAW instead of JPG, you can adjust the light balance temperature in post-processing. When you see professional photographers taking a photograph of a grey card, they are using this as a fixed reference that they can then use when editing the picture and set the exact color temperature.

The camera flash has been designed to produce light that records as pure white or 5500 degrees Kalvin. (Light temperature is measured in degrees Kelvin.) The following chart shows the temperatures for various standard light conditions.  

The higher the number, the warmer the image, and the lower the number, the cooler the image looks.  The following photograph taken on a sunny day (Daylight 5,500°) has been changed to the various color temperature settings.  You can see how each one changes the how warm or cool the photograph feels.  Sometimes you want the color in your photograph to be exactly as you saw it.  Other times, you can adjust the color temperature for an ‘artistic’ look.