culling  measurements that are not representative of the photospheric velocity, one should have reliable  measurements, but will necessarily have an incomplete sample. A potential way to avoid this bias would be to perform a double-Gaussian fit. We have not investigated how this method performs with noisy data.

SYNOW Models {#s:synow}
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To further understand the nature of the Ca H&K feature, we use the SN spectrum-synthesis code [SYNOW]{} [@Fisher97] to create simple [SYNOW]{} spectral models. We specifically use these models to test how temperature can affect the profile and look for trends between the Ca H&K profile shape and other spectral features. Although [SYNOW]{} has a simple, parametric approach to creating synthetic spectra, it can provide insight on basic trends in SN SEDs. To generate a synthetic spectrum, one inputs a blackbody temperature ($T_{\rm BB}$), a photospheric velocity ($v_{\rm ph}$), and for each involved ion, an optical depth at a reference line, an excitation temperature ($T_{\rm exc}$), the maximum velocity of the opacity distribution ($v_{\rm max}$), and a velocity scale ($v_{e}$). This last variable assumes that the optical depth declines exponentially for velocities above $v_{\rm ph}$ with an $e$-folding scale of $v_{e}$. The strengths of the lines for each ion 