Color temperature, a term borrowed from physics, is the measurement (in Kelvins) of a color’s intensity on a scale of blue to red. In broad terms, color temperature refers to the visible light an object radiates based on its inherent heat.
While the red end of the color spectrum has a color temperature of 1,800K, colors that appear bluer fall within 16,000K. The following are the color temperatures of everyday sights: sunrise and sunset registers at around 1,600K; an electronic camera flash has a color temperature of 5,500K; a deep blue, cloudless sky emits 20,000K.
Ironically, warmer objects (those registering higher Kelvin temperatures) emit blue, a color that is traditionally considered to be a cooler color on the color wheel. Conversely, cooler objects radiate more reds, typically associated as a warmer color. For example, throughout a light bulb’s life, the bulb will appear red when it is hot. However, when the bulb is its hottest (i.e. just before it burns out), it will produce a visibly bluish light.
When the color of a photograph is off, the color sensitivity of the film hasn’t been properly calibrated to the color temperature of the photographed object. If you aren’t sure how to pair an object’s color temperature with the appropriately sensitive film, try using filters on your camera lens. Such filters can effectively balance a photo’s color.
Color temperature is also an important term in computer technology. Knowing your monitor’s range of color temperatures is key when you are choosing software for your system.