Two important parameters for white LEDs are CCT and CRI. CCT is the Correlated Color Temperature – defined as wavelength for white LEDs. This is dependent upon the white spectrum of the LED and how the eye perceives the light. Different color temperatures affect how illuminated objects are perceived. The CCT from 1000 to 3500 K brings the warm effects while the CCT from 6000 K appears cold. From 4000 K to 5000 K, there is the neutral feeling of white light.