Color temperature

Color temperature refers to the frequency of the lightwave being emitted, and how that frequency affects the color that objects under it appear. Many people notice one result of color temperature--that white objects at dusk tend to appear a light purple. Other results of color temperature tend to be less noticable except through electrical equipment such as cameras and monitors.

Experimentation with color temperature is obvious in many Stanley Kubrick films; for instance in Eyes Wide Shut the light coming in from a window was almost always conspicuously blue, whereas the light from lamps on end tables was fairly orange. Indoor lights and arc-sodium lights typically give off an orange hue; fluorescent lighting tends to be more yellow.

Most video cameras can adjust for color temperature by zooming into a white object and setting the white balance (telling the camera "this object is white"); the camera then shows true white as white and adjusts all the other colors accordingly. White-balancing is necessary especially indoors under fluorescent lighting and when moving the camera from one lighting situation to another.

Cinematographers can also white-balance to objects which aren't white, downplaying the color of the object used for white-balancing. For instance, cinematographers can bring more warmth into a picture by white-balancing off something light blue, like faded blue jeans; in this way white-balancing can serve in place of a filter or lighting gel when those aren't available.

Right now this article mainly discusses the practical application of color temperature in cinematography -- we need information on the physics of it...