Top panel: Δm_-10 for 14 SNe Ib/c in the SDSS sample as a function of the effective wavelength of each filter in the SN rest frame (violet, green, red, dark yellow and cyan represent ugriz filters). Bluer bands rise faster than redder bands for most of the objects. Blue, red and magenta labels correspond to SNe Ib, Ic and Ic-BL, respectively. Central panel: same as in the top panel, the line fitted to the data (and plotted in red) corresponds to Δm_-10(λ) = −2.01 × 10^-4λ + 2.26, with Δm_-10 expressed in magnitudes and λ in Å. Uncertainties on Δm_-10(λ) are ~0.66 mag. Bottom panel: cumulative distribution functions for the r-band Δm_-10 of SNe IIb (4), Ib (13), Ic (9), and Ic-BL (8) from the SDSS sample and from the literature. Shaded areas indicate the uncertainties for Δm_-10. SNe Ic and Ic-BL show higher values of Δm_-10 when compared to SNe Ib (p-values =0.18 and 0.003, respectively).