Intrinsic JHK colours for dwarf (blue line) and giant (red line) stars, from Bessell & Brett (1988). The red point represents a star with H − K = 0.26 and J − H = 0.79. The distance between the point to the giant curve is 0.08 dex, and to the dwarf curve is 0.13 dex, therefore the star is classified as giant. The shaded area represents the H − K range for which the curves overlap, and no classification can be correctly performed. In those cases, the star is classified as dwarf.