Illustration of how the simulated data was produced and processed. Left panel: input color–magnitude diagram of 47Tuc. Overplotted is the isochrone that was used to assign spectra to the individual stars. Upper panels: cut-out from an HST image of 47Tuc (upper middle); whitelight image of a simulated crowded field datacube centred on the HST footprint (upper right). The lower right panel shows the deblended spectrum of the star marked with a white circle. The input spectrum of this star is overplotted.