It then goes back down the scale as it sets. So if you’ve ever asked what color is daylight, imagine how the sun, for example, rises at approximately 1800 Kelvin and changes from red to orange to yellow and to white as it rises to over 5000 Kelvin at high noon. Colors and light go from red, orange, and yellow (warm - incandescent) to blue and white (natural daylight). This system is based on the color changes of a black metal as it is heated from a cold black to a white hot state. But why is color temperature measured in degrees Kelvin (K)? This temperature is based on the principle that any object will emit light if it is heated to a high enough temperature and that the color of that light will shift in a predictable manner as the temperature is increased. The color temperature of a light source is a numerical measurement of its color appearance. Color temperature is how cool or warm the light source appears. The higher the CRI value, the better the light source is at interpreting colors accurately.Ĭolor Temperature: Refers to the way color groups are perceived – the psychological impact of lighting. By comparing the appearance of a colored object under an artificial light source to its appearance under an incandescent light already set at 100 CRI.

So how important is CRI to you? Depending on the project or use of your bulbs, it can be equally important as the look. Sources with CRI values less than 50 are generally regarded as rendering colors poorly, that is, colors may appear unnatural. The higher the CRI of the light source, the 'truer' it renders color. Incandescent lamps and daylight have a CRI of 100, the highest possible CRI. CRI is a more important consideration for retail lighting design than it is for office lighting.Īny CRI rating of 80 or above is considered high and indicates that the source has good color properties. Compact fluorescent lamps are graded at 82-86 CRI, which is considered high quality color rendering. There are two standard measurements for the color characteristics of light: 'color rendering index' (CRI), a term used to describe the extent to which an artificial light source is able to render the true color of objects as seen by natural outdoor sunlight which has a CRI of 100, and 'color temperature', which expresses the color appearance of the light itself.Ĭolor Rendering Index: Incandescent is used as the base reference of 100 CRI.

Halogen flood light bulb