The color temperature settings control the way in which a projector projects white and color. A true white is around 6500° Kelvin; if the projector is told to display white at a higher color temperature, whites will tend to have a bluish hue to them. If you set the projector to a lower setting, whites will tend to have a more reddish hue.
Why change the color temperature at all? First, projectors can come from the factory with their color temperatures set too high or too low for your tastes. Secondly, different sources will look better at different color temperatures. Computer images can look brighter and more vivid at a higher color temperature while movies are better at or below 7000° Kelvin. Generally projectors’ setting will range between 5500° K- 9000°K, although they are not usually marked as degrees Kelvin. Typically, you will find color temperature controls labeled as low, mid and high, or warm, normal and colder.
Color temperature is defined in scientific terms as a black body — a hypothetical object that absorbs all of the energy that falls on it. When heated, the black body turns to color. At first, it will turn red, then yellow, and ultimately blue and violet. The temperature at which the black body matches the color of a given light source is said to be the color temperature of that light. The following chart gives examples of some common color temperatures.