Left: blometric light curves of SN 2007on (black) and SN 2011iv (red) constructed from observations constraining the flux extending from uvm2 to the H band ( ~2250–18 800 Å; UVOIR). Complementing the majority of SN 2011iv measurements are a handful of additional bolometric points covering the wavelength range extending from the UV (1620 Å) to K_s (24 900 Å). The error bar on the bolometric luminosity is presented in the top right of the plot, and assumes an error in the adopted distance modulus of ±0.2 mag. Also shown is the bolometric light curve (line) of model 5p0z22.18b presented in Sect. 6.2. Right: UV (blue), optical (green), and NIR (red) flux fractions of the total bolometric light curve of SN 2011iv computed from observed spectroscopy. The open green symbols illustrate reduced optical flux fractions from 3480 Å to 8630 Å, while the solid green symbols represent the full range from the atmospheric cutoff at 3050 Å to 8630 Å. The UV fraction extends from either 1620 Å (STIS, solid blue symbols) or 1900 Å (UVOT, open blue symbols) to 3050 Å, and the NIR fraction extends from 9000 Å to 24 900 Å. Shown as connected filled squares is the fraction of flux distributed among the different wavelength regimes for model 5p0z22.18b. This includes the predicted MIR fraction (24 900 Å to 1 000 000 Å), which drives the difference between the observed and modelled UVOIR light curves beginning around a month past maximum brightness.