Coloring Rendering Index (CRI) – CRI represents the quality of light and its faithfulness to render colors correctly, that is, to enable us to perceive colors as we know them. The ideal CRI is 100, and some incandescent bulbs approach this level. LEDs and CFLs use different design components in trying to equal the CRI of incandescent bulbs. LED bulbs CRI ratings range from 70 to 95, and the best CFLs have ratings in the mid 80s. The entire line of Viribright A19 bulbs, for example, features a CRI of 90+ Warm White making them one of the highest in the industry.
Correlated Color Temperature (CCT) – is the measure used to describe the relative color appearance of a white light source. CCT indicates whether a light source appears more yellow/gold/orange or more blue, in terms of the range of available shades of “white.” CCT is given in kelvins (unit of absolute temperature). 2700K is “Warm”, 4000K is “Cool” and 6000K is “Daylight”. The typical light color we are used to in indoor home lighting is “warm”, 2700K.
Lumen – a unit of standard measurement that is used to describe the amount of light contained in an area as perceived by the human eye. The more lumens, the brighter the light. You can use lumens to compare the brightness of any bulb, regardless of the technology behind it, and regardless of whether it’s incandescent, CFL or LED.
In practical application, when buying a light bulb, we should look for bulbs which produce more light but consumes less energy. Understanding lumens as a measure of brightness makes it easier to select the most efficient bulb for your application. This is also important