Examples of the four spectral regions used to measure the veiling of CI Tau. In each panel, we show two different nights, representing a small and a high veiling estimated for this target. We show the CI Tau spectrum in black and the residual profile (in red) obtained after subtracting the veiled template. The V819 Tau template spectra are also displayed before (orange) and after (blue) applying the veiling correction. The photospheric lines were removed in the residual profiles, showing that the veiling was accurately determined for most nights.