Simultaneous isochrone fitting to derive the cluster R_V using three CMDs: HST (left panel), 2MASS JK_S from Valenti et al. (2007) (top right panel), and Gaia DR3 (bottom right panel). The isochrones are coloured according to their R_V value. In each panel, the best solution is represented by the solid dark red isochrone. For the two right panels, the χ² analysis is plotted in the inset plot, and the dots are coloured by the same colour as the corresponding isochrone.