5

Color Balance
Color balance refers to the relative strength of the red, green, and blue channels that
constitute an image. For example, a blue-tinted image has a strong blue channel and
weaker green and red channels.
The Color Balance filter lets you adjust the relative balance of all three color channels of
an image at once—for example, lowering the blue channel and raising the red and green
channels to reduce blue tinting and yield an image that appears more orange and warm.
Color balance also relates to color temperature, which describes the quality of light in an
image. For example, sunlight is generally more bluish than tungsten light, which is more
orange. In professional film and video productions, white-balancing the camera before
shooting usually ensures that whites in an image are neutral (with all three color channels
balanced evenly). However, film stocks, optical filters, and digital white-balance settings
can modify the tint of an image.
Note: The imbalanced color channels caused by a dominant color temperature in the
lighting of an image is often referred to as a color cast.
You can use the Color Balance filter to adjust the three color channels of an image to
eliminate a color cast or introduce one. Here are some uses for the Color Balance filter:
• To correct problems in lighting—for example, rebalancing an image that’s too orange
to appear more neutral.
• To match two images to one another—for example, matching the quality of light on
an actor in a foreground green screen clip to the lighting in a background image.
1027Chapter 19 Using Filters