Example third-signature plots derived from HARPS data and solar FTS, convolved to R = 110 000, for spectral types ranging from F7V (top left) to M2V (bottom left), chosen to sample the scale factor range. Shown are shifts v_conv for individual lines (blue circles) and results binned by line depth (red triangles with error bars for MAD, black for the error of the median). The best-fit, scaled, solar third signature is shown (orange curve, fitted through the red markers).