Composite spectra constructed from all spectra with epochs in the range (3−8). The left panel composite is based on spectra with colour below average, the right panel one is based on spectra with colour above average. The plots show both composite (red) and individual (grey) spectra. The average SALT colours and epochs are printed for each composite, as well as the pEW for the indicated region. The dashed square marks a region where a small feature seems to exist only in the low colur sample (SALT c  <  0.03), either because it is not resolved or because it is very rare among the higher colour SNe (0.03  <  SALT c  <  0.3).