Observed late-time bolometric light curve (solid blue lines) and the fraction of light that could be attributed to ⁵⁶Ni after accounting for CSM interaction (dashed, red). The dotted green curves show the ⁵⁶Ni light curve after adding the missing IR flux (up to 5 μm). The IR correction pushes the light curves back to the regime of PISN models that produce 25–44 M_⊙ of ⁵⁶Ni. Even in the case of a substantial contribution from CSM interaction, a total amount of 25–44 M_⊙ of ⁵⁶Ni appears to be essential to power SN 2018ibb.