Pixiq

The automatic functions on a digital camera are like automatic transmissions in cars—they quickly lull us into a false sense of security. In effect, we don't have to think as much about the mechanics of driving, and our driving skills actually suffer. Automation builds dependency. So I’d like to take up arms against a sea of unnecessary automation. In doing so, I’d also like to talk about Automatic White Balance (AWB).

All light has color. We’re all familiar with the warm yellow-red glow of house lights and the cool green of office fluorescents. Now, digital cameras are wonderful, but they are no substitute for the human eye and common sense, because our brains adapt to the color of light so fast that most of the time we hardly notice or see the yellow-red of tungsten lights or the green of fluorescents. It’s a phenomenon of our perceptual system called “color constancy,” and it makes a white piece of paper appear the same white whether under sunlight, on a table in a tungsten-lit room, or on an office desk, even though the different lighting conditions should make the paper look, respectively, purely white, with a red cast, or with a green cast.

Neither film nor digital cameras can do this color constancy thing, so ways have been developed to photographically adjust for the color of the light. Filters can be used to balance film, while digital cameras do it by finding a white area in a scene, comparing it to a standard, and removing any color cast. The reasoning is that when the whites are clean, all the colors in the photo are going to be looking pretty good too. Works for laundry, why not for photography?

Like automatic car transmissions, the white balance (WB) control promises to make things effortless so we can literally take our eyes off the road, allowing us to just point and shoot. And we poor mortals; we hear the siren song of the sweet temptress of automation whispering in our ears, “Do it. It’s so easy”—and we buy in.

But there’s a glitch. WB controls don’t work all the time; maybe even more of the time than we suspect.

I got to thinking about this as I was photographing an XIII Century French church. I was happily shooting away when a little voice in my head said, “Check the pictures.”

Over the years I’ve learned to listen to little voices in my head, and so I checked my LCD to see what I had. Whoa, momma was I glad I did. The pale yellowish walls of the church were coming out anything but the right color.

I looked at my white balance settings and quickly switched from AWB, holding the camera so I could see the LCD with one eye as I tried different WB settings and compared the monitor to the actual scene with my other eye. To my shock the color differences were huge—but none of the WB settings produced the color that matched the church wall! You can see what I saw in the images in this post. So I stepped back and tried to figure out what was happening.

Then, like a bolt of strobe light I had a revelation. There wasn’t any white in the scene for the camera to use for adjustment. The yellow walls were tricking the camera into cooling off the scene. The frame of the church archway (marked AWB) is almost colorless. The Daylight WB frame is also too gray. Now look at the Cloudy WB; it’s gone the other way, it’s too yellow. And the same happens with the Shade WB setting, which warms the image to compensate for the coolness of the light on a cloudy day or in the shade of a tree.

At this point you may wonder why I did not shoot in RAW format? I didn’t do so because there was no guarantee that my visual memory of the scene would be accurate enough to get the color temperature correct when working with my RAW editor at some future time.   

Now I had just come from the local bakery and had a baguette propped up in my camera bag. Remembering a trick I’ve used in the studio with complex shooting situations, I pulled the white wrapper off the bread and held it out in front of camera, using it as a makeshift white card. I set the camera to Custom WB and took a frame to get my own personal WB setting.

Recording a Custom white balance is not difficult with almost any camera. You go to the WB menu page and look to select Custom, or to the strange symbol you can see in the illustration below. Hold something white like a white card or baguette wrapper at about arm’s length. Frame it so it fills most of the image area. Next, by pressing the shutter button you’ll record a Custom WB that will serve you well.

I shot the rest of my pictures using this Custom setting and, thankfully, you can now see the church’s true colors in the following photo.

The white card technique is one easy way to fight back when automation turns against you. It’s super cheap and gives you better pictures too. And using it teaches you a lot about light and the way we can’t quite trust our own eyes.

After this experience I bought a 5x7-inch (12.7 x 17.8 cm) white card in a stationary shop and keep it folded my camera bag just in case I don’t have a freshly wrapped baguette handy. 

Photos and text 2010 Steve Meltzer