Color temperature
You use the color temperature of the light as a standard way to describe the color of the light and how it relates to pure white. Your eyes adjust to the different colors of light automatically but the sensor in your digital camera can’t. While a white piece of paper looks the same to you under a variety of light sources, it doesn’t to the camera. The color temperature is measured on the Kelvin scale.
The lower the number on the Kelvin scale, the more red and orange the color is, while the higher the number, the more blue there is. By knowing what the color of the light is, you can set the camera to accurately capture the scene by using the proper white balance. White balance The white balance setting on your camera tells the sensor what type of light the photo is being taken under, and renders the scene as accurately as possible. Setting the white balance before you take the photo will help to make sure that your photograph turns out the way you want it to. There are ways to adjust the white balance in postprocessing using the camera’s software or any of the photo editing programs. This is easier if you shoot using the RAW file type (which I wholeheartedly recommend), but it is now possible to adjust the white balance of other image file types as well. Every camera manufacturer, and in some cases each different camera model, can have slightly different settings for each of the white balance presets.
- Auto white balance. Most cameras have an Auto white balance setting (see Figure 2.4), which tries to set the correct white balance based on the information reaching the sensor. This setting is usually good for many situations, but as with all automatic settings, it does have a few drawbacks. The first is that because the camera sets the white balance for every shot, there can be slight differences even if the subject and location are the same. If you need a series of photographs to look the same, then you need to pick one of the other settings. The second drawback is that the camera, no matter how smart it might seem, doesn’t actually know what you are shooting. The Auto white balance is just a guess and can never be as accurate as when you set it yourself.
- Daylight. The daylight setting tells the camera that the light reaching the sensor is in the 5000 to 5500K range. This is the color of the sun’s light at noon where there are no clouds. While this is an accurate representation of the light, it can look a little cold, especially when shooting people. A better choice for shooting people is the cloudy setting.
- Cloudy. This setting tells the camera that the light is slightly colder, so it compensates by adding a little more red/orange to the scene and makes people look just a little healthier.
- Flash. This setting is used to match the color of the light produced from the camera’s flash. It is a little bluer than daylight and is very close to the cloudy setting.
- Shade. The light in deep shade is very blue or cold. When you set the white balance to shade, the camera adds more red to balance out the color.
- Tungsten or Incandescent. Incandescent lights fall to the warmer side of the Kelvin scale, so when using this white balance, the camera adds blue to the scene. You will notice that photographs of people taken indoors seem to be warmer than those taken outdoors.
- Fluorescent. Fluorescent lighting is really tough on photographers. It can change depending on the gas used in the tubes and the cycle of electricity used to power the tubes. Because the lights work on a cycle, the shutter speed can also affect the color of the light. This setting tries to match a fluorescent bulb’s lighting but can give you mixed results, depending on the actual bulbs.
- Kelvin. Many cameras, especially the semiprofessional and professional models, allow you to enter the actual Kelvin temperature of the light. This allows you to fine-tune the white balance and set the exact temperature you want.
- Custom. Some cameras allow you to take a photo of a white surface, and then let the camera adjust the white balance and use that as a setting under those lights. This is great when shooting under mixed lighting where none of the presets is exactly what you want.
