Cameras and eyes see light differently.

How the Eye Sees Light (1)

In the section on complementary colors it was indicated that a mix of equal parts of red, blue, and green light would produce white light. In reality white light is 59% green, 30% red, and 11% blue. How is this contradiction explained? It isn't really a contradiction. Your eyes are not equally sensitive to all colors of light. What looks like equal amounts of red, green, and blue aren't really equal amounts at all. The CCDs, however, are equally sensitive to all colors of light. For your eyes to see white on the television screen, the TV camera must produce a picture that is 59% green, 30% red, and 11% blue.

Color Temperature

If you've ever taken photographs outside and then gone indoors and taken more pictures without using a flash, you've gotten some disappointing results. Chances are that the pictures taken outside looked great, but those taken indoors had an orange/yellow cast to them. What you've seen is the result of the difference of color temperature. Color temperature is a way of measuring the color characteristics of light. Color temperature has nothing to do with heat or cold. The higher the color temperature, the more blue there is in the light. The lower the color temperature, the more orange there is in the light. The light outside on a bright, sunny day might be around 5600° K (Kelvin, the scale used to measure color temperature). The light in your home is probably around 2600° K. This is why the colors in the photographs look so different. If you use a flash indoors, the light will be the same color temperature as daylight and your photographs will look fine. You don't see the change in color temperature because your eyes and brain compensate for you. If you see a person in a yellow jacket outdoors and then the two of you go indoors, your brain knows that it's the same jacket and it couldn't have changed colors. Your brain sees the jacket as the same color. A camera can't do that.

1.  Approximate color temperature of some common light sources.

2.  Color TV camera, showing location of filter wheel.