Color temperature

Color temperature refers to the frequency of the light being emitted, and how that affects the color that objects appear. Color temperature is something that people don't often notice except through electrical equipment such as a camera or monitor, though many people notice how white objects at dusk tend to appear a light purple. 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 more orange. Indoor lights and arc-sodium lights typically give off an orange hue.

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 adjusts the colors to show true white as white. White-balancing is necessary especially indoors under fluorescent lighting. Cinematographers can also white-balance to objects which aren't white, resulting in the color of that object being downplayed in the image. For instance, you 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 when a filter isn't available.