Average deviation of the measured Ti lines from the mean, as a function of wavelength, equivalent to Fig. 4. Green squares are Ti I lines, pale green diamonds are Ti II lines and the dark green square is a Ti I line falling out of the criteria. The bluest part of the spectrum (<4740 Å) is only usable for the brightest stars, so these points and their standard deviations are determined from measurements in ≤6 stars.