Ejecta composition at the start of the cmfgen simulations for models r0e2 (top; M_e = 9.69 M_⊙; post-explosion time of ~1.1 d) and r6e4BH (bottom; M_e = 2.55 M_⊙; post-explosion time of ~4.6 d). The dashed line corresponds to the ⁵⁶Ni mass fraction at the given time. The top axis gives the Lagrangian mass coordinate in the ejecta (zero corresponds to the base of the ejecta). In model r6e4BH, most of the O-rich shell has been accreted into the 4 M_⊙ BH. In particular, the outer layers where He is present now overlap with the ⁵⁶Ni-rich regions.