Illustration of the influence of metals on the emergent spectrum for a Type Ibn model derived from model he4p0. The default model (see also Fig. 5) is shown in blue. The same model in which we excluded the Fe/He shell (hence no ⁵⁶Ni and associated decay products) is shown in red. Finally, the model in which we excluded the Fe/He shell and scaled by a factor of 0.1 the abundance of all metals heavier than Ar is shown in yellow.