Many of you probably have seen the white balance, or WB, settings on your camera but have elected to just put it on auto and not give it another thought. Setting a proper white balance will ensure that you get good color in your images.
To do this, we need to understand the science behind white balance. All light has what is called a color temperature, which is measured in Kelvin. The range of Kelvin temperature goes from 2,500 to 10,000 degrees. The lower the Kelvin color temperature, the cooler or bluer the light is; the higher the Kelvin temperature, the warmer or redder the light. Middle ground is a Kelvin temperature of 5,500, which is full sun daylight. The trick is to set your white balance setting on your camera to match the type of light in which you're photographing.
Most digital single-lens reflex cameras have several presets for your white balance, in addition to the auto setting. There are settings for daylight, shade, cloudy, fluorescent, flash, tungsten and custom.
Let's take each setting and break it down. Auto is useful if you are shooting quickly in changing light conditions. The auto setting on most newer cameras is very good to get you close. It does pose problems in very warm light or very cool light. To really fine-tune your color, try some of the more specific presets. The daylight setting would be a good one to use in bright sunlight, and should render good natural color, as long as you are shooting in bright sunlight between 10 a.m. and 2 p.m.
As the shadows grow, the light becomes cooler, and photos take on a blue hue, so we need to compensate for that. Try using the shade setting to increase the Kelvin temperature to warm up the scene. Cloudy weather is cooler yet (Kelvin temperature, that is), so we need to increase the Kelvin temperature, and the cloudy setting works well for this type of light.
You may have noticed that photos taken inside a room lit by fluorescent lighting take on a green cast. Try using the fluorescent setting to bring the color back to normal.
One note on fluorescent lighting: Different types of fluorescent lights emit different Kelvin temperatures, so you might have better luck with the auto setting. If you decide that you are going to use an electronic strobe or flash to light a dark image, you should put your preset on flash. Modern strobes are manufactured to emit a burst of light that's a little cooler than daylight, so the flash setting will warm up the image. The tungsten light preset will give you good color when shooting photos inside with incandescent bulbs, which are typical house lights.
The next option -- and the best, in my opinion -- is a custom white balance. To perform a custom white balance, you will need a piece of gray cardboard about 8 by 10 inches; most camera stores sell these for this purpose. Set your camera on custom WB, then photograph the gray card in the light that you're going to be photographing in, getting as close as possible to the card. It's important that you make a good exposure, but you don't need to have the card in focus. Next, follow the prompts in your camera to save this image as your WB setting. As long as the light doesn't change, you will have perfect color.
This week's assignment is to photograph several scenes under different lighting conditions and experiment with the presets to determine how accurate they are. One word of advice: Always set your camera back to auto after a day of shooting to ensure that the next time you pull out your camera, you will at least be close to a good WB and not face any surprises.
Jay Sousa can be reached at email@example.com.