This "lightening" and "darkening" you describe actually makes a lot of sense in terms of another way of connecting phycis and color, if we by "lightened" mean "

This "lightening" and "darkening" you describe actually makes a lot of sense in terms of another way of connecting phycis and color, if we by "lightened" mean "higher color temperature", and for "darkened" "lower color temperature". (Color temperature according to Wikipedia is "temperature of an ideal black-body radiator that radiates light of comparable hue to that of the light source") https://en.wikipedia.org/wiki/Color_temperature https://en.wikipedia.org/wiki/Color_temperature