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White Balance

The color of light can vary dramatically and is measured with a scale called "degrees Kelvin". The "Kelvin" scale starts at "absolute zero" (0° kelvin =−273.15° Celsius or -459.67° Fahrenheit). The sensor in your camera has to know what the color of the ambient light is in order to adjust each image so that the colors look correct. Mid-day sun has a color temperature of 5,500° Kelvin. The light at dusk and/or dawn has a color temperature much warmer than that - about 3,500° Kelvin. In cloudy weather, the color temperature is a cool 6,500° Kelvin.  Since the color temperature can vary so dramatically, we have make an adjustment in our digital cameras so that they know how to adjust the colors in our images. This is done with the "White Balance" adjustment.

When shooting JPEG images, the images are PERMANENTLY adjusted to the white balance that either the camera or you select. When shooting RAW images, you can change the white balance when editing the image on a computer. 

Auto White Balance vs Manually set White Balance
Every camera has an "AUTO" White Balance setting and almost all cameras also have a manual white balance setting. The auto setting tries to figure out the color of the light and adjust the resulting image accordingly.  But, it's not always accurate. You are ALWAYS better off to tell your camera what the color of the light is BEFORE you take the picture.  The only downside of this is that you have to remember to reset the white balance before taking another picture with different light.

Adding/Coloring light
You can add light to help change the color of the light.  This is most commonly done using electronic flash.  A very good way to add light using electronic flash is "fill-in" flash so that you are not providing ALL of the light, but are using some of the ambient light available.  You can even "color" the light of the electronic flash by using colored filters over the flash.

Modify the Light with filters - Film only
You can easily modify the light so that the film "thinks" it's seeing 5,500° Kelvin light (what film expects to see). This is commonly done with filters. This isn't something you want to do with digital photography. The following chart shows the relationships between different types of film (on the right), different kinds of light sources (° Kelvin) and different filters (in the center).  For example, when shooing with daylight film and using a 3,000 ° Kelvin light source, you would want to use a 80A filter - where the line drawn from the film type to the light type intersects the Mired value. (Note: MIRED is an acronym and is related to color temperature).


Modify the Light - using Digital
Digital cameras don't need color compensating filters.  They have a feature called "White Balance".  The white balance refers to the compensation that can take place in the digital camera to "correct" the color of the light.  Most digital cameras have options such as:  Automatic White Balance, Daylight, Tungsten, Fluorescent, Cloudy, Flash, Preset, etc.  When set to "Automatic" - usually the default for a digital camera - the camera tries to make an intelligent decision as to what color the light is.  But it usually only works within a small range of light (i.e., 3,500° - 7,000°) and doesn't always work that well.  If shooting on a cloudy day, you're always better off to select "cloudy" than "automatic".  Just don't forget to set it back!  The best option is to use the PRESET option if your camera has it.  This allows you to "measure" the color of the light using a white or neutral gray object.  This way you're always assured of the best color compensation.

Even when taking RAW images you need to properly adjust white balance!  Here are 4 images all taken with tungsten light - the first three are RAW and the last is a JPG.

1. The first image was taken as RAW and AUTOMATIC white balance.
2. The second image was taken as RAW and TUNGSTEN white balance.
3. The third image was taken as RAW and a measured PRESET white balance was used.
4. The fourth image was taken as a JPG and a measured PRESET white balance was used.

white balance test

The last three images have the best white balance.  The "Automatic" white balance (first image) is the worst (look at the background!) - the reason for this is the automatic setting can't compensate enough for tungsten light. The last two are the best (although you wouldn't know what the real colors are, these are the most realistic).  You can especially see a difference in the background colors. The lower background was black text on white paper.

The first three images were RAW images and could have been easily modified to correct for the incorrect white balance, but... EVERY correction you make in an image reduces its quality.  Shoot an accurate white balance up front and you get a better image and save yourself time on the computer!

All images and content © Copyright 1999-2010 Bert Sirkin