Color temperature is not color rendering. I am referring to how well color is rendered under a source as based on the full spectrum the sun puts out. This is measured by determining the spectral power distribution of a source in addition to measuring it against a series of color chips.
“White” LEDs begin as a royal blue LED. They use the ultraviolet spectrum to excite phosphors either on the chip or remotely mounted (similar to the Philips lamp, with the orange/yellow illuminated pads). These phosphors then emit “white” light. Cooler color temperatures are more efficient, as the phosphors are required to do less work. But the very nature of exciting phosphors (like a fluorescent lamp) has always resulted in a lower CRI than simply heating up a wire.
