Back in the days of film, there were only two kinds of film: daylight and tungsten. Most pros shot on transparency film and most of that was daylight balanced, which is 5500 degrees Kelvin. Type B Tungsten film is balanced for 3200 K. (Less common Type A Tungsten film is balanced for 3400 K.)
Today with digital cameras, you now have a lot of choices on how to set the white balance (WB) control. The easiest choice is Auto-WB. But it is usually not the best choice.
Why Auto WB is sub-optimal
Digital cameras use algorithms that examine the picture content and make some intelligent guesses about the color temperature of the light source. For instance one Auto-WB algorithm is “grey world”, everything averages out to middle grey. Another Auto-WB algorithm is to look at patches of highlights that haven’t clipped and guess that they are the color of the light source. The key point is that these are just guesses. They are not measuring a reference color.
Another reason Auto-WB is not the best is because the camera will adjust the WB for from shot to shot even if the light does not change.
Manual WB puts you in control
There are at least three ways to manually set the white balance on your camera.
Method#1. You can manually set the WB to daylight, tungsten, fluorescent, Cloudy or Shade based on the observed lighting conditions. Do this if you are in a hurry. You will get approximately the correct white balance.
Method #2. The optimum way to set the white balance is to measure the color temperature of the light falling on your scene and then set this in the camera. With a color temperature meter, measure the color temperature in degrees Kelvin and put that number into your camera. But not many people carry a color meter with them anymore. Fortunately, your digital SLR can function as a color meter.
Method #3. Placing a Kodak grey card in the scene and then set the WB using your cameras Custom WB function. This is probably the most practical way to set the WB.
I am confident that your photographs will have more accurate color if you set the white balance manually, rather than relying on your camera’s Auto WB.
