Tutorial 3 - Why MacAdams and not +/- K?

FineWHITE_Tutorial3_graphic1_E40

Because of the different sizes and orientations of these ellipses, also in relation to the lines of equal CCT, a "+/- Kelvin" range does not really give you information about the true homogeneity.

Picture

Tutorial 3 - Why MacAdams and not +/- K?

Ellipse A: +/- 1000 K

Ellipse B: +/- 225 K

BUT

Homogeneity A = Homogeneity B