If you look closely at the fine print in the technical datasheets or product boxes of lighting products, you will find reference to an ANSI specification C78.377-2008, which is associated with Correlated Color Temperature (CCT). This specification sets standards, or more specifically, tolerances, for color consistency among light sources. How these tolerances—what is considered an acceptable deviation in color temperature—are determined is through applying MacAdam ellipses.  In this blog, we will take a closer look at MacAdam ellipses and why the lighting industry uses them to define the color point specification of lamps.