The color of light can vary enormously, and this can have a big impact on the way your photographs look. From photographing in sunlight to shooting indoors, the color of light keeps changing. If left uncompensated, even small variations in lighting conditions give a color cast to an image, a tint of color that affects the whole of the photograph. While the initial photograph may have a color cast, it is not the end of the story because your digital camera has the ability to adjust for the varying lighting conditions. This setting is called White Balance. We tend to keep the setting on Auto White Balance which works accurately for average scenes in normal lighting but some lighting conditions or subjects can fool it. It will be good to know a little about color temperature to help understand white balance better.
What is Color Temperature?
Even though our eyes can adjust to varying color, we can still tell that during sunrise or sunset, the light looks much warmer than at midday. This effect is much more noticeable on images. To help understand this variation, the color of a light source is given a value known as the color temperature, which is expressed in units of degrees Kelvin (K). Check the chart below for the typical values of the most common light sources.
|Light Sources||Color Temperature in K|
|Clear blue sky||10,000-15,000|
|Cloudy or overcast||6,000-7,000|
|Early morning or late evening sunlight||3,500-4,500|
|Studio photoflood bulbs||3,200-4,000|
|Household light bulb||3,000-3,500|
|Sunrise or sunset||2,000-3,000|
Let’s not go into the science behind the concept of color temperature but do remember that cooler lights have a higher color temperature and warmer lights have a lower color temperature. This is contrary to the cultural associations attributed to colors, in which “red” is “hot”, and “blue” is “cold”. Our eyes can quickly adjust to different color temperatures. A white paper may look a different shade of white under different lighting conditions in the photographs even though our eyes still tend to see it as white.
Color temperature is closely related to white balance. In digital photography, the terms are sometimes interchangeably used. White balance setting tells the camera about the lighting conditions in the scene which helps the camera in producing correct colors in the photograph.
How to Set the Correct White Balance
Setting the white balance can be accomplished either in-camera before taking a photograph or during post-processing if shooting in RAW.
As mentioned earlier, automatic white balance setting is good in general lighting conditions, but many a time the camera system can struggle to differentiate between the color of light falling on the subject, and the color of the subject itself. When the subject consists largely of a single color, the automatic white balance tries to adjust the color to give a neutral result, which ends up producing unacceptable colors.
Manual Settings for White Balance
In addition to the automatic setting, there are different manual white balance options in-camera you can choose from. The exact settings may vary between cameras and manufacturers, but here are some options that are available across all digital cameras.
Incandescent/ Tungsten – For shooting indoor scenes lit by household light bulbs with a color temperature of about 3000K.
Fluorescent – Fluorescent lights do not have a precise color temperature but a value of 4000K is usually good to correct for this type of light
Sunlight – The digital equivalent to daylight film; Color temperature – 5500K
Flash – Electronic flash has almost the same color temperature as sunlight, though some cameras have a color temperature setting of 6000K to compensate for the slightly cooler flash light
Cloudy – For shooting under cloudy skies; Color temperature – 6000K
Shade – When shooting in shade, there is usually a blue cast in the photos. This setting compensates for it by setting a color temperature of 7000K.
Preset/ Custom – Using this setting, you can take a reading of the color temperature from your subject. You need a neutral gray or a white reference point that is in exactly the same lighting conditions as your subject. You need to fill your frame with an 18% gray card and take a white balance reading from it and then set the same on the camera to give you exactly the right color.
Using a gray card. Photo by Wolfgang Lonien, on Flickr
If you photograph in RAW, you can set the white balance during post-processing. The same options as mentioned above are also usually available in the image editing program, apart from the Kelvin setting which you can use to fine tune the white balance.
If you have utilized a gray card in a photo, you can use the white balance tool on the photo to set the white balance from the gray card. You can then synchronize the photos shot under the same lighting with this setting to speed up your workflow.
Creative Uses of White Balance
Producing a neutral result does not always give you the photo you want. You might want your image to look warmer rather than neutral or cold. You can easily achieve this by selecting a white balance with a higher color temperature than your light source. So, in direct sunlight, rather than using the correct 5500K setting, you can use the Cloudy (6000K) or Shade (7000K) setting. This is especially true in the case of sunrise or sunset photos. Selecting the “right” white balance would completely destroy the warmth in these shots. Again, you can retain the warm glow by setting a Daylight white balance or enhance it by setting Cloudy or Shade.
Using the tungsten white balance setting during daylight, combined with a 1 or 2 stop underexposure (i.e. -1 or -2 exposure compensation), you can simulate night.
References, and other useful links
Chris Rutter, The Essential Color Manual for Photographers, Rotovision
How to set white balance – a detailed article on white balance by Ken Rockwell
White Balance Gone Wild – a Flickr group with a nice collection of photos using white balance creatively
How to Set Your White Balance Manually – a great post, right here on LightStalking, about manually setting white balance
A Brief Guide to Color Management for Photographers – a useful post, right here on LightStalking, on color management and calibration