I was looking at the sample image provided on the linked article for hue differentiation where for each of the three rows, the strips of colour differ by 5%. The three rows differ by brightness only. The article used this image to illustrate that "lighter blues is more distinguishable than darker blues, while darker magentas are more distinguishable than lighter ones", but to me both lighter blues and lighter magentas were more distinguishable than the darker counterparts.