Have you ever taken a photograph inside your house only to find that your picture had an eerie yellow tint that made your subject look jaundiced? The reason for the weird tint is caused by the naturally warm hue (color temperature) of the incandescent light bulbs which are common light sources in homes. Likewise, if you have ever taken a picture in a store or doctor's office, your photograph probably had a blue tint to it; this is caused by the cool color temperature of a row of florescent lights. We don’t see the light’s color because our eyes have the ability to filter out the tint but our cameras aren't as highly evolved as our eyes and often need our guidance to help create the proper white balance.
For the sake of clarity, color temperature, is the natural color a light source has. White balance is how the color white appears is your photograph. Luckily, we have the ability to manipulate the color temperature of our photos by changing the white balance. Typically there are two ways to do this. One is using a preset mode, the other is to create a custom white balance.
White Balance Preset Modes
Automatic white balance, indicated by the letters AWB, gives your camera permission to decide what the white balance should be in a given situation. Typically it finds the brightest portion of your frame and sets that as white. Many photographers find that pictures tend to be a little bit too cool in this mode regardless of their shooting conditions. Camera companies do this because slightly cooler tones are harder to detect and less distracting than overly warm tones.
The tungsten setting, typically depicted by a little light bulb, is for indoor use when your scene or subject in lit by a traditional light bulb. The light produced by filament light bulbs is very warm and often gives off an orange and yellow glow in photographs even though it does not appear that way to the human eye. To combat the orange tinge, the tungsten setting adds a considerable amount of blue into the photo. This setting is also helpful for candle lit scenes.
The florescent setting, typically indicated by a bar with light rays coming out of it, counteracts the slightly cool greenish tones produced by florescent lighting by adding a touch of warmth and magenta as a counterbalance.
The daylight setting, shows as a little sun icon on most cameras, is for use in the direct sunlight during the day when the skies are clear. Some cameras do not have this setting because the unfiltered natural light is typically very close to white. Camera that do have this function use it to tell the camera that the white is pure white or close to it with a nearly imperceptible light, light blue tint added by the sky and doesn’t need to be adapted. It is typically used as an alternative to the auto white balance option.
The shade preset, depicted by a picture of a house with lines on one side signifying shade, is for situations when your subject is in a lightly shaded area or a situation where you have open shade. Open shade is when your subject is in the shade but the background is well lit. This preset adds a touch of orange to fight the slight blue tint found in shaded light.
The cloudy preset, indicated by a little cloud, is for photographs taken under cloudy overcast clouds. Clouds often diffuse the sun’s natural light which removes harsh shadows but it also adds a heavy blue tinge to your pictures. The cloudy present adds warmth at a much higher concentration that with the florescent or shade presets.
The flash preset, shown as a little lightning bolt arrow on your white balance menu, is used for when you are using the on camera flash, a mounted Speedlight or some other type of flash.
Setting a Custom White Balance
While it is possible to fix white balance issues in post-processing, it can be tedious, especially in instances where you have multiple photos to edit. When taking multiple photographs in the same location, creating a custom white balance can streamline your post-processing workflow by removing a step.
In order to do this you must first take a picture of a white piece of paper or 18% gray. An 18% gray card is a piece of cardboard that is colored what modern cameras consider neutral. Photographers swear by them but a white piece of paper will usually suffice. For the sake of ease, we will use the gray card for the following set up tutorial.
First set up your gray card. If you are photographing a person, have them hold it in place. If you are photographing an inanimate object prop the card up or hold it out in front of you. It should be held or propped in the lighting your actual subject will be lit by, at the approximate focal point so that the light falling on them or it is the same as the light falling on your gray card. The light will measure the brightest portion of the paper as white so avoid any bright spots that are typical for your location.
Most cameras require you to fill up the majority of your frame with gray card or white paper. Do this by moving towards the subject. Do not have the subject come forward as it could change the light source, direction, or intensity.
After taking the photo of the gray card, each camera has an option to set it as your custom white balance from menu. The actual protocol for doing so is different for each make and model so read your manual.
Knowing the basics of color temperature and how to alter the way your camera synthesizes light is an important skill. Knowing how light works is one of the most important skills any photographer can have and knowing how to manipulate it in your camera on location or in the studio is going to save you hours of monotonous post-production work that could have easily been avoided by paying attention to your light sources and the affects they have on your photographs.
The Science of Color Temperature
I’m a bit of science geek and love to know why things happen. I know I can’t be the only one interested in the scientific principles that affect white balance so here is a little explanation. Color temperature is, by definition, “the temperature at which a black body could emit radiation of the same color as a given object”. In regards to photography, color temperature gives us a scale by which to measure the visual attributes of our light sources.
Color temperature is measured in Kelvins. Much like Celsius and Fahrenheit, Kevin is a measurement of heat. If you were to heat up a piece of metal in a fire that piece of metal would change colors are it got increasingly hotter. First it would turn red, then orange, yellow, white, and eventually a blue that would get progressively darker as the metal was heated, assuming it didn’t melt first.
Color temperatures in the red, orange and yellow range are on the low end of the Kelvin scale and typically have measurements of 3000K or less; these are called warm temperatures. Color temperatures in the blue range are on the high end of the Kelvin scale and usually measurement of 5500K or more; they are referred to as cool color temperatures.
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