Zoomed-in Hess diagram of the selected field b320. Solid black line follows the derived reddening vector (see text), while the dashed black box defines the polygon-region used to select the stars in the sample for the color excess calculations. Additionally, the red solid line follows Nishiyama et al. (2009) reddening law, and intersects the solid black line at (J−K_s) = 0.635, which is roughly the (J−K_s)₀ of the reddening corrected RC+RGB sequence at their peak overdensity in the CMD.