Have you ever taken photographs in a gymnasium only to have the photo come out with a sickly yellow tinge? This frustrating situation has to do with the color of light and the white balance in your camera. Fortunately, there are ways to fix this problem either in the camera or in post-processing.
Most gyms are poorly lit to begin with, and some older gymnasiums even have mixed lighting in the form of poor overhead light combined with natural light streaming in through windows near the ceiling. Either setting adds up to less than ideal conditions, and contributes to that yellowish tinge you've noticed in your photos.
To understand what is happening, we need to talk a little bit about the properties of light. Visible light isn't really white; it’s actually a rainbow of colors ranging from red to violet. Light has a color temperature. While our eyes can adjust to the differences in color and temperature, even the sensors in the best cameras aren't able to do what the human eye can do. That’s what the WB (white balance) on your camera handles.
Color temperature is measured in Kelvins (K). The higher the color temperature, the bluer the light will be. The lower the temperature, the more more yellow or orange or even red the light will appear. Daylight at high noon has a temperature of about 5000 degrees Kelvin. Outdoor shade is between 7000-8000 K. An overcast sky is generally 6000-7500 K. And for a typical school gym, the light temperature is about 3000 degrees Kelvin.
To correct the yellow tint of your pictures, you need to try a few things. Look at your camera's dial and notice the different icons: a house with one side in shade, another for florescent lighting, clouds, a sun, and a light bulb (indicating tungsten lighting). Tungsten is often a good option for those occasions when you are shooting in a gym.
Try setting your camera’s white balance to auto during the pre-game warmups and check your results. Auto white balance should handle the gym coloring pretty well, but it still might be just off. After all, presets are just an approximation. If you are shooting in RAW, then it’s an easy fix in post-processing using a program such as Adobe Lightroom or Photoshop. However if you are shooting in JPEG, you need to get the white balance right in the camera. (And even if you are shooting in RAW, there are some who will argue it’s always better to get it right the first time in camera instead of spending any additional time or effort in post-processing.)
If the auto white balance preset doesn’t look right, try tungsten and see how the results look. Scroll through the various presets and watch in the LCD as they change to reflect the different white balance options. Most DSLRs also have the ability to allow you to dial in the actual Kelvin setting. Start with 3000K and begin tweaking it if needed (perhaps down to 2800K or up to 3200K).
DSLRs also have the ability to save a custom white balance in the camera. A custom white balance basically tells your camera that under these conditions this setting is considered white. If you find a setting that you like and you are going to be shooting a lot in the same gym, save the setting in the camera under the Custom Settings option in your menu. It will be a quick time saver in the future. Just remember to change your custom white balance back when you leave!