Upper panel: g – r versus r – i color locus of stars extracted from a 1° × 1° field around the NGC 2264 cluster (photometry from Venuti et al. 2014). The expected color properties of MS dwarfs as a function of their spectral type, and the associated uncertainties, are traced and labeled following Covey et al. (2007) to guide the eye. Lower panel: r – i versus i – J color locus for the same population of stars shown in the upper panel. The J-band photometry is extracted from 2MASS.