Starting with the IES Lighting Handbook, 5th edition, the section “Color Temperature” on p 5-11 states that a blackbody radiator would be “white (neutral) at about 5000°K.” [Kaufman 1972 ...

Color temperature is based on Planck’s Law which explains the changing color of a heated black body radiator over a certain temperature range. When a [theoretical] black body radiator is heated, the ...