Color Temperature

The mapping here is the theoretical Planckian (black-body) colour, before any gamma, monitor whitepoint, or chromatic-adaptation transform. Real displays run their own pipeline — values around 6500 K (D65) and 5500 K (movie / camera) are the most colour-accurate landmarks.

Above ~6600 K the black body becomes saturated cyan and then saturated blue. The eye perceives it as washed-out white because of chromatic adaptation, but the RGB triple really does pin red at 255 in the warm side and blue at 255 in the cool side.

Sort of. WB is the inverse: a camera measures the scene's apparent temperature and applies the opposite tint so neutral subjects render neutral. The same Kelvin scale is the input — 5500 K daylight, 3200 K tungsten, etc.

Because the eye's sensitivity is not flat across the spectrum, and it shifts as light levels drop — colour vision fades and the peak moves towards blue-green, which makes warm light seem weaker in the evening than a meter says it is. It is also why a room lit at 2700 K needs more measured light to feel as bright as one at 4000 K.

Warmer as the day ends, in practice. Cooler light around 4000 K and above supports alertness and suits work, while 2700 K reads as evening and is easier to relax under; matching the light to the hour is what makes a room feel right rather than any single correct number. What matters more than the exact figure is consistency — mixed temperatures in one room are what actually looks wrong.