Dependence of the bolometric light curve and the hydrogen mixing on the chemical composition of the hydrogen-rich envelope for the late-time 1D N20 models with the representative radioactive ⁵⁶Ni mass from Table 2. Panel a): bolometric light curves of models N20-P (black line) and N20-C (red line). Panel b): mass fraction of hydrogen as function of velocity in models N20-P (black line) and N20-C (red line). Panels c) and d): mass fractions as functions of velocity in models N20-P and N20-C, respectively. The red line is the mass fraction of radioactive ⁵⁶Ni, and the magenta line represents iron-group elements except for ⁵⁶Ni (see also Fig. 2). All profiles of the mass fractions are given at t = 50 days.