Spectral properties of our model set at about 5 (top left), 15 (top right), 30 (bottom left), and 85 d (bottom right) after explosion. We stack our ten models from top to bottom in order of increasing H content, using the same color coding as before. For the montage at 5 d, we show the quantity λ²F_λ in order to reduce the contrast between UV and optical ranges. We also shade the flux associated with bound-bound transitions of H I (light shade) and He I (dark shade).