The (B − V)₀, (V − R)₀ and (V − I)₀ colour curves of SN 2008fv, corrected for the Galactic reddening (Cardelli et al. 1989) S law and R_V = 3.1 and for the host galaxy reddening with R_V = 2.9 (see Sect. 3.2 for details). The colour curves of labeled SNe, corrected for their respective colour excess, are also show. The Lira (1995) relation (dashed line) predicts a lower E(B − V) than derived from the maximum light and adopted as the “true” host galaxy reddening (see text). As a consequence, the Lira relation does not provide a good fit of the dereddened colour curves.