Source density across the NGC 6397 CMD in I_E − Y_E filters obtained for the sources observed within the Euclid field of view. Panels (a) and (b) show the CMDs obtained by Massari et al. (2025) and Libralato et al. (2024a), respectively, from the same data. Panels (c) and (d) show the CMDs derived in this work with the two photometric methods described in Sect. 3. No quality selections have been applied to these catalogues.