Planckian Locus is a term often associated with colour of a light-source and how ‘hot’ it looks. It relates to the path (or locus) that the colour of an incandescent (or Black Body) takes through a particular chromaticity space as the blackbody temperature changes. As a black body heats up its Colour Temperature changes from deep red at low temperatures through orange, yellowish-white, white and finally bluish-white at very high temperatures.
