(Part two, continued from Shooting in Variable Light: Tricks of the Trade)

White balance is the black sheep of the family when it comes to ensuring your digital shoot looks its best in variable light. It’s so easy to focus on subject matter, exposure, and composition and then, almost as an afterthought, realize  that “Oh yeah, white balance – well, I guess I’ll just leave it on the ‘auto’ setting.”

I can’t tell you how many times this has happened to me, and, to be honest, there’s a good reason for it. Unlike bad composition, the wrong ISO setting, or depth of field that’s too narrow, white balance is something that I really can fix quite easily in post-processing—especially with the tools ACDSee Pro provides.

This isn’t to say that you should totally ignore white balance, or even use the wrong settings—that’s not my point. What I’m saying is that there’s some good news about it in digital photography: One of the easiest things to forget is also one of the easiest things to deal with after-the-fact.

Let’s start from the beginning, at least briefly, with the first point of confusion: White balance is based on color temperature. Measured in degrees of Kelvin (identified by a “K”), a lower color temperature is actually referred to as a warmer light. For example, an incandescent light bulb has a warm yellow glow that is measured lower in Kelvin (2700-3300K) than, for example, the “cold” blue light from a flash (5500-6000K).

Most higher-end SLRs have several ways of adjusting how they measure and record color temperature: through presets designed to match common color temperature ranges of various types of lights, using an automatic white balance setting, by specifying the specific temperature, or by creating a custom setting based on a test photo of your environment.

If you put your camera on auto white balance, you are depending upon it to accurately read the ambient light and setting its own white balance temperature to match that reading. If the light is mixed—say for example a combination of sunlight, regular light bulbs, and fluorescent light as you move through a room—then you will have to remain in precisely the same type of light without it changing in order to get an accurate color reproduction in your image.

If you preset your camera using one of the little icons (typically showing a sun, a fluorescent bulb, a conventional light bulb, clouds, etc.), then you are assuming that the light temperature will remain constant. So if you are shooting outside and you’ve preset your white balance to sunlight, and then you move indoors to fluorescent lighting or put a flash on the camera, if you don’t change that preset then the color reproduction in digital images will be incorrect.

If you use a specific color temperature, then you probably know that it needs to match the color of your ambient light precisely. You would typically get this by taking a temperature reading with a colorimeter; this is somewhat common in higher-end studios or professional lighting scenes (like, for example, a movie set).

Lastly, taking a custom reading will allow you to get an accurate reading of a space where the color temperature is relatively constant. For example, if you’re in an evenly lighted room with the same types of lights, or if you’re shooting subjects that are consistently lighted, then you can measure that with your camera and set it at that point. I often do this when shooting fencing at high-end venues, where the lighting on the finals “strip” is constant on the fencers and I want the uniforms to show up as white-whites. (Various cameras achieve custom settings differently—check your manual for how to take a custom setting.) Some photographers use 18-percent gray cards to take a photo used in creating a custom setting; I also use a product called the “ExpoDisc” that diffuses the ambient light and lets me measure it quite accurately to get a custom setting.

The main thing to remember is that if you have anything but an automatic white balance set, you will need to change it if the light changes—your camera won’t know to do so. Additionally, some types of lighting feature variable color temperatures; fluorescent lighting is notorious for playing this little game. You can take a successive series of images with the same white balance setting, with what seems to be exactly the same light, and each photo will be different – because the fluorescent light bulbs are constantly fluctuating temperatures.

As with all things, knowing how these things work ahead of time is half the battle. If you’re aware of the lighting situation, you can make the most of it. For example, if you know you’ll be in mixed light and moving around, then using auto-white balance is the best thing to do – even though it is far from foolproof. You may very well get a mix of colors in images of the same types, as the light changes (and those changes can be quite subtle). Or if you’re using a flash, your auto-white balance will automatically be set for that, but if another light source overpowers the flash, the color may very well go haywire.

The bottom line of the lighting situation is that no matter how perfectly you set your white balance, unless your light is guaranteed to be absolutely consistent (which is rare), you may get fluctuations in color temperature and some of them might not be very desirable. This is where the powers of ACDSee Pro shine.

Often after a fencing championship, I run my photos through the white-balance rinse cycle: a batch process using an auto-exposure setting in ACDSee Pro (to do this, make sure you have the contrast and color adjustment clicked and not just contrast). Very often, this is just enough to balance-out any significant color variations to the point that a large set of images—say photos from a big reception—are completely acceptable and the colors are satisfactorily consistent. As I’ve written in the past, I usually combine this with a reduced sharpening edit, as well (not for the light, but to make the photos just a tad more crisp).

Inevitably, however, there are images where the color just isn’t what it should be. Sometimes this can actually be acceptable, especially if it’s relatively consistent. Shooting in Paris at a large fencing grand prix a few years ago, for example, when I got the white balance custom-set for the white fencing uniform, everything in the background turned blue—something invisible to the naked eye until the image appeared on my computer screen. At first I was alarmed, but then I realized that it actually looked reasonably cool, and my subject was perfectly adjusted to the color, so I let it go. Since then, I’ve experienced this a number of times and have gotten used to it.

More color adjustments in ACDSee are available under the “color” setting in the edit menu and can also be batch processed—even using a specific Kelvin temperature setting, if you’re so inclined. You can also select, just like on your camera, to batch-process images based on the typical presets such as cloudy, sunny, fluorescent, etc.. Be aware, however, that if you batch process images to a specific color setting or preset, any photos taken from differing light will, in turn, produce different color reproductions, and that may not be what you want.

While you can edit specific colors in images, sliding the Red-Green-Blue in varying degrees, this often ends up being a bit of a fool’s errand, in my experience, and you find yourself making adjustments to fix your adjustments. Unless you have a lot of time and you’re doing a lot of work on a specific image for an upcoming major photography show or international competition, I don’t often suggest this as a solution to a simple or basic color reproduction problem.

Finally, back to the Arnold Classic and Governor Schwarzenegger’s photo shoot at the fencing championship. I was using a flash that, combined with the overhead sodium lights, produced a yellow tint to images as seen in the first example of the Governator with a fencing epee. By simply using the auto-exposure control in ACDSee Pro, as I suggested above, the color becomes significantly more accurate. And that’s the kind of intelligent, easy, but very important post-processing I like when I don’t make the precisely right choice at the scene …