Color temperature refers to the apparent color light that exits a light source. It’s an important performance characteristic to evaluate lamps because the lamps color temperature creates the mood within the space you are lighting and can influence buying behavior or work performance. Also referred to as ‘Correlated Color Temperature (CCT), the apparent color of a light source is measured in Kelvin or “k”.
In describing color temperatures, a low color temperature corresponds to “warm” or a red-amber appearance like incandescent lamps at 2700 kelvin. Fluorescent lamps operating at 3500 kelvin give off a “neutral” white light. “Cool” light comes from sources like cool white fluorescent lamps operating at 4100 kelvin or above. In color temperature, the higher the kelvin temperature, the whiter and then bluer the light.